ATT&CK explorer

Adversaries may store data in "fileless" formats to conceal malicious activity from defenses. Fileless storage can be broadly defined as any format other than a file. Common examples of non-volatile fileless storage in Windows systems include the Windows Registry, event logs, or WMI repository.(Citation: Microsoft Fileless)(Citation: SecureList Fileless) Shared memory directories on Linux systems (`/dev/shm`, `/run/shm`, `/var/run`, and `/var/lock`) and volatile directories on Network Devices (`/tmp` and `/volatile`) may also be considered fileless storage, as files written to these directories are mapped directly to RAM and not stored on the disk.(Citation: Elastic Binary Executed from Shared Memory Directory)(Citation: Akami Frog4Shell 2024)(Citation: Aquasec Muhstik Malware 2024)(Citation: Bitsight 7777 Botnet)(Citation: CISCO Nexus 900 Config). Similar to fileless in-memory behaviors such as Reflective Code Loading and Process Injection, fileless data storage may remain undetected by anti-virus and other endpoint security tools that can only access specific file formats from disk storage. Leveraging fileless storage may also allow adversaries to bypass the protections offered by read-only file systems in Linux.(Citation: Sysdig Fileless Malware 23022) Adversaries may use fileless storage to conceal various types of stored data, including payloads/shellcode (potentially being used as part of Persistence) and collected data not yet exfiltrated from the victim (e.g., Local Data Staging). Adversaries also often encrypt, encode, splice, or otherwise obfuscate this fileless data when stored. Some forms of fileless storage activity may indirectly create artifacts in the file system, but in central and otherwise difficult to inspect formats such as the WMI (e.g., `%SystemRoot%\System32\Wbem\Repository`) or Registry (e.g., `%SystemRoot%\System32\Config`) physical files.(Citation: Microsoft Fileless)

Adversaries may smuggle commands to download malicious payloads past content filters by hiding them within otherwise seemingly benign windows shortcut files. Windows shortcut files (.LNK) include many metadata fields, including an icon location field (also known as the `IconEnvironmentDataBlock`) designed to specify the path to an icon file that is to be displayed for the LNK file within a host directory. Adversaries may abuse this LNK metadata to download malicious payloads. For example, adversaries have been observed using LNK files as phishing payloads to deliver malware. Once invoked (e.g., Malicious File), payloads referenced via external URLs within the LNK icon location field may be downloaded. These files may also then be invoked by Command and Scripting Interpreter/System Binary Proxy Execution arguments within the target path field of the LNK.(Citation: Unprotect Shortcut)(Citation: Booby Trap Shortcut 2017) LNK Icon Smuggling may also be utilized post compromise, such as malicious scripts executing an LNK on an infected host to download additional malicious payloads.

Adversaries may encrypt or encode files to obfuscate strings, bytes, and other specific patterns to impede detection. Encrypting and/or encoding file content aims to conceal malicious artifacts within a file used in an intrusion. Many other techniques, such as Software Packing, Steganography, and Embedded Payloads, share this same broad objective. Encrypting and/or encoding files could lead to a lapse in detection of static signatures, only for this malicious content to be revealed (i.e., Deobfuscate/Decode Files or Information) at the time of execution/use. This type of file obfuscation can be applied to many file artifacts present on victim hosts, such as malware log/configuration and payload files.(Citation: File obfuscation) Files can be encrypted with a hardcoded or user-supplied key, as well as otherwise obfuscated using standard encoding schemes such as Base64. The entire content of a file may be obfuscated, or just specific functions or values (such as C2 addresses). Encryption and encoding may also be applied in redundant layers for additional protection. For example, adversaries may abuse password-protected Word documents or self-extracting (SFX) archives as a method of encrypting/encoding a file such as a Phishing payload. These files typically function by attaching the intended archived content to a decompressor stub that is executed when the file is invoked (e.g., User Execution).(Citation: SFX - Encrypted/Encoded File) Adversaries may also abuse file-specific as well as custom encoding schemes. For example, Byte Order Mark (BOM) headers in text files may be abused to manipulate and obfuscate file content until Command and Scripting Interpreter execution.

Adversaries may utilize polymorphic code (also known as metamorphic or mutating code) to evade detection. Polymorphic code is a type of software capable of changing its runtime footprint during code execution.(Citation: polymorphic-blackberry) With each execution of the software, the code is mutated into a different version of itself that achieves the same purpose or objective as the original. This functionality enables the malware to evade traditional signature-based defenses, such as antivirus and antimalware tools.(Citation: polymorphic-sentinelone) Other obfuscation techniques can be used in conjunction with polymorphic code to accomplish the intended effects, including using mutation engines to conduct actions such as Software Packing, Command Obfuscation, or Encrypted/Encoded File.(Citation: polymorphic-linkedin)(Citation: polymorphic-medium)

Adversaries may use compression to obfuscate their payloads or files. Compressed file formats such as ZIP, gzip, 7z, and RAR can compress and archive multiple files together to make it easier and faster to transfer files. In addition to compressing files, adversaries may also compress shellcode directly - for example, in order to store it in a Windows Registry key (i.e., Fileless Storage).(Citation: Trustwave Pillowmint June 2020) In order to further evade detection, adversaries may combine multiple ZIP files into one archive. This process of concatenation creates an archive that appears to be a single archive but in fact contains the central directories of the embedded archives. Some ZIP readers, such as 7zip, may not be able to identify concatenated ZIP files and miss the presence of the malicious payload.(Citation: Perception Point) File archives may be sent as one Spearphishing Attachment through email. Adversaries have sent malicious payloads as archived files to encourage the user to interact with and extract the malicious payload onto their system (i.e., Malicious File).(Citation: NTT Security Flagpro new December 2021) However, some file compression tools, such as 7zip, can be used to produce self-extracting archives. Adversaries may send self-extracting archives to hide the functionality of their payload and launch it without requiring multiple actions from the user.(Citation: The Hacker News) Compression may be used in combination with Encrypted/Encoded File where compressed files are encrypted and password-protected.

Adversaries may use junk code / dead code to obfuscate a malware’s functionality. Junk code is code that either does not execute, or if it does execute, does not change the functionality of the code. Junk code makes analysis more difficult and time-consuming, as the analyst steps through non-functional code instead of analyzing the main code. It also may hinder detections that rely on static code analysis due to the use of benign functionality, especially when combined with Compression or Software Packing.(Citation: ReasonLabs)(Citation: ReasonLabs Cyberpedia Junk Code) No-Operation (NOP) instructions are an example of dead code commonly used in x86 assembly language. They are commonly used as the 0x90 opcode. When NOPs are added to malware, the disassembler may show the NOP instructions, leading to the analyst needing to step through them.(Citation: ReasonLabs) The use of junk / dead code insertion is distinct from Binary Padding because the purpose is to obfuscate the functionality of the code, rather than simply to change the malware’s signature.

Adversaries may smuggle data and files past content filters by hiding malicious payloads inside of seemingly benign SVG files.(Citation: Trustwave SVG Smuggling 2025) SVGs, or Scalable Vector Graphics, are vector-based image files constructed using XML. As such, they can legitimately include `<script>` tags that enable adversaries to include malicious JavaScript payloads. However, SVGs may appear less suspicious to users than other types of executable files, as they are often treated as image files. SVG smuggling can take a number of forms. For example, threat actors may include content that: * Assembles malicious payloads(Citation: Talos SVG Smuggling 2022) * Downloads malicious payloads(Citation: Cofense SVG Smuggling 2024) * Redirects users to malicious websites(Citation: Bleeping Computer SVG Smuggling 2024) * Displays interactive content to users, such as fake login forms and download buttons.(Citation: Bleeping Computer SVG Smuggling 2024) SVG Smuggling may be used in conjunction with HTML Smuggling where an SVG with a malicious payload is included inside an HTML file.(Citation: Talos SVG Smuggling 2022) SVGs may also be included in other types of documents, such as PDFs.

Windows 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). (Citation: Microsoft WinRM) It may be called with the <code>winrm</code> command or by any number of programs such as PowerShell. (Citation: Jacobsen 2014)

Adversaries may schedule data exfiltration to 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 C2 Channel or Exfiltration Over Alternative Protocol.

An 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.

Windows service configuration information, including the file path to the service's executable or recovery programs/commands, 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. Adversaries may also intentionally corrupt or kill services to execute malicious recovery programs/commands. (Citation: Twitter Service Recovery Nov 2017) (Citation: Microsoft Service Recovery Feb 2013)

Adversaries may explicitly employ a known encryption algorithm to conceal command and control traffic rather than relying on any inherent protections provided by a communication protocol. Despite the use of a secure algorithm, these implementations may be vulnerable to reverse engineering if necessary secret keys are encoded and/or generated within malware samples/configuration files.

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 OS 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. Adversaries may use the information from System Owner/User Discovery during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions. Various utilities and commands may acquire this information, including <code>whoami</code>. In macOS and Linux, the currently logged in user can be identified with <code>w</code> and <code>who</code>. On macOS the <code>dscl . list /Users | grep -v '_'</code> command can also be used to enumerate user accounts. Environment variables, such as <code>%USERNAME%</code> and <code>$USER</code>, may also be used to access this information. On network devices, Network Device CLI commands such as `show users` and `show ssh` can be used to display users currently logged into the device.(Citation: show_ssh_users_cmd_cisco)(Citation: US-CERT TA18-106A Network Infrastructure Devices 2018)

**This technique has been deprecated. Please use Path Interception by PATH Environment Variable, Path Interception by Search Order Hijacking, and/or Path Interception by Unquoted Path.** Path 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. (Citation: TechNet MS14-019) 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) (Citation: Microsoft Subkey) 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., <code>C:\unsafe path with space\program.exe</code> vs. <code>"C:\safe path with space\program.exe"</code>). (Citation: Baggett 2012) 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 <code>C:\program files\myapp.exe</code>, an adversary may create a program at <code>C:\program.exe</code> that will be run instead of the intended program. (Citation: SecurityBoulevard Unquoted Services APR 2018) (Citation: SploitSpren Windows Priv Jan 2018) ### 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, <code>%SystemRoot%\system32</code> (e.g., <code>C:\Windows\system32</code>), 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 <code>C:\example path</code> precedes <code>C:\Windows\system32</code> is in the PATH environment variable, a program that is named net.exe and placed in <code>C:\example path</code> 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. (Citation: Microsoft CreateProcess) (Citation: Hill NT Shell) (Citation: Microsoft WinExec) 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 <code>net user</code>. 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 <code>cmd.exe /C net user</code> will execute "net.com" instead of "net.exe" due to the order of executable extensions defined under PATHEXT. (Citation: MSDN Environment Property) Search order hijacking is also a common practice for hijacking DLL loads and is covered in DLL Search Order Hijacking.

Adversaries 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.

Adversaries may attempt to manipulate features of their artifacts to make them appear legitimate or benign to users and/or security tools. Masquerading occurs when the name or location of an object, legitimate or malicious, is manipulated or abused for the sake of evading defenses and observation. This may include manipulating file metadata, tricking users into misidentifying the file type, and giving legitimate task or service names. Renaming abusable system utilities to evade security monitoring is also a form of Masquerading.(Citation: LOLBAS Main Site)

Adversaries may attempt to mimic features of valid code signatures to increase the chance of deceiving a user, analyst, or tool. Code signing provides a level of authenticity on a binary from the developer and a guarantee that the binary has not been tampered with. Adversaries can copy the metadata and signature information from a signed program, then use it as a template for an unsigned program. Files with invalid code signatures will fail digital signature validation checks, but they may appear more legitimate to users and security tools may improperly handle these files.(Citation: Threatexpress MetaTwin 2017) Unlike Code Signing, this activity will not result in a valid signature.

Adversaries may abuse the right-to-left override (RTLO or RLO) character (U+202E) to disguise a string and/or file name to make it appear benign. RTLO is a non-printing Unicode character that causes the text that follows it to be displayed in reverse. For example, a Windows screensaver executable named <code>March 25 \u202Excod.scr</code> will display as <code>March 25 rcs.docx</code>. A JavaScript file named <code>photo_high_re\u202Egnp.js</code> will be displayed as <code>photo_high_resj.png</code>.(Citation: Infosecinstitute RTLO Technique) Adversaries may abuse the RTLO character as a means of tricking a user into executing what they think is a benign file type. A common use of this technique is with Spearphishing Attachment/Malicious File since it can trick both end users and defenders if they are not aware of how their tools display and render the RTLO character. Use of the RTLO character has been seen in many targeted intrusion attempts and criminal activity.(Citation: Trend Micro PLEAD RTLO)(Citation: Kaspersky RTLO Cyber Crime) RTLO can be used in the Windows Registry as well, where regedit.exe displays the reversed characters but the command line tool reg.exe does not by default.

Adversaries may rename legitimate / system utilities to try to evade security mechanisms concerning the usage of those utilities. Security monitoring and control mechanisms may be in place for legitimate utilities adversaries are capable of abusing, including both built-in binaries and tools such as PSExec, AutoHotKey, and IronPython.(Citation: LOLBAS Main Site)(Citation: Huntress Python Malware 2025)(Citation: The DFIR Report AutoHotKey 2023)(Citation: Splunk Detect Renamed PSExec) It may be possible to bypass those security mechanisms by renaming the utility prior to utilization (ex: rename <code>rundll32.exe</code>).(Citation: Elastic Masquerade Ball) An alternative case occurs when a legitimate utility is copied or moved to a different directory and renamed to avoid detections based on these utilities executing from non-standard paths.(Citation: F-Secure CozyDuke)

Adversaries may attempt to manipulate the name of a task or service to make it appear legitimate or benign. Tasks/services executed by the Task Scheduler or systemd will typically be given a name and/or description.(Citation: TechNet Schtasks)(Citation: Systemd Service Units) Windows services will have a service name as well as a display name. Many benign tasks and services exist that have commonly associated names. Adversaries may give tasks or services names that are similar or identical to those of legitimate ones. Tasks or services contain other fields, such as a description, that adversaries may attempt to make appear legitimate.(Citation: Palo Alto Shamoon Nov 2016)(Citation: Fysbis Dr Web Analysis)

Adversaries may match or approximate the name or location of legitimate files, Registry keys, or other resources when naming/placing them. This is done for the sake of evading defenses and observation. This may be done by placing an executable in a commonly trusted directory (ex: under System32) or giving it the name of a legitimate, trusted program (ex: `svchost.exe`). Alternatively, a Windows Registry key may be given a close approximation to a key used by a legitimate program. In containerized environments, a threat actor may create a resource in a trusted namespace or one that matches the naming convention of a container pod or cluster.(Citation: Aquasec Kubernetes Backdoor 2023)

Adversaries can hide a program's true filetype by changing the extension of a file. With certain file types (specifically this does not work with .app extensions), appending a space to the end of a filename will change how the file is processed by the operating system. For example, if there is a Mach-O executable file called <code>evil.bin</code>, when it is double clicked by a user, it will launch Terminal.app and execute. If this file is renamed to <code>evil.txt</code>, then when double clicked by a user, it will launch with the default text editing application (not executing the binary). However, if the file is renamed to <code>evil.txt </code> (note the space at the end), then when double clicked by a user, the true file type is determined by the OS and handled appropriately and the binary will be executed (Citation: Mac Backdoors are back). Adversaries can use this feature to trick users into double clicking benign-looking files of any format and ultimately executing something malicious.

Adversaries may abuse a double extension in the filename as a means of masquerading the true file type. A file name may include a secondary file type extension that may cause only the first extension to be displayed (ex: <code>File.txt.exe</code> may render in some views as just <code>File.txt</code>). However, the second extension is the true file type that determines how the file is opened and executed. The real file extension may be hidden by the operating system in the file browser (ex: explorer.exe), as well as in any software configured using or similar to the system’s policies.(Citation: PCMag DoubleExtension)(Citation: SOCPrime DoubleExtension) Adversaries may abuse double extensions to attempt to conceal dangerous file types of payloads. A very common usage involves tricking a user into opening what they think is a benign file type but is actually executable code. Such files often pose as email attachments and allow an adversary to gain Initial Access into a user’s system via Spearphishing Attachment then User Execution. For example, an executable file attachment named <code>Evil.txt.exe</code> may display as <code>Evil.txt</code> to a user. The user may then view it as a benign text file and open it, inadvertently executing the hidden malware.(Citation: SOCPrime DoubleExtension) Common file types, such as text files (.txt, .doc, etc.) and image files (.jpg, .gif, etc.) are typically used as the first extension to appear benign. Executable extensions commonly regarded as dangerous, such as .exe, .lnk, .hta, and .scr, often appear as the second extension and true file type.

Adversaries may masquerade malicious payloads as legitimate files through changes to the payload's formatting, including the file’s signature, extension, icon, and contents. Various file types have a typical standard format, including how they are encoded and organized. For example, a file’s signature (also known as header or magic bytes) is the beginning bytes of a file and is often used to identify the file’s type. For example, the header of a JPEG file, is <code> 0xFF 0xD8</code> and the file extension is either `.JPE`, `.JPEG` or `.JPG`. Adversaries may edit the header’s hex code and/or the file extension of a malicious payload in order to bypass file validation checks and/or input sanitization. This behavior is commonly used when payload files are transferred (e.g., Ingress Tool Transfer) and stored (e.g., Upload Malware) so that adversaries may move their malware without triggering detections. Common non-executable file types and extensions, such as text files (`.txt`) and image files (`.jpg`, `.gif`, etc.) may be typically treated as benign. Based on this, adversaries may use a file extension to disguise malware, such as naming a PHP backdoor code with a file name of <code>test.gif</code>. A user may not know that a file is malicious due to the benign appearance and file extension. Polyglot files, which are files that have multiple different file types and that function differently based on the application that will execute them, may also be used to disguise malicious malware and capabilities.(Citation: polygot_icedID)

An adversary may attempt to evade process tree-based analysis by modifying executed malware's parent process ID (PPID). If endpoint protection software leverages the “parent-child" relationship for detection, breaking this relationship could result in the adversary’s behavior not being associated with previous process tree activity. On Unix-based systems breaking this process tree is common practice for administrators to execute software using scripts and programs.(Citation: 3OHA double-fork 2022) On Linux systems, adversaries may execute a series of Native API calls to alter malware's process tree. For example, adversaries can execute their payload without any arguments, call the `fork()` API call twice, then have the parent process exit. This creates a grandchild process with no parent process that is immediately adopted by the `init` system process (PID 1), which successfully disconnects the execution of the adversary's payload from its previous process tree. Another example is using the “daemon” syscall to detach from the current parent process and run in the background.(Citation: Sandfly BPFDoor 2022)(Citation: Microsoft XorDdos Linux Stealth 2022)

Adversaries may match or approximate the names of legitimate accounts to make newly created ones appear benign. This will typically occur during Create Account, although accounts may also be renamed at a later date. This may also coincide with Account Access Removal if the actor first deletes an account before re-creating one with the same name.(Citation: Huntress MOVEit 2023) Often, adversaries will attempt to masquerade as service accounts, such as those associated with legitimate software, data backups, or container cluster management.(Citation: Elastic CUBA Ransomware 2022)(Citation: Aquasec Kubernetes Attack 2023) They may also give accounts generic, trustworthy names, such as “admin”, “help”, or “root.”(Citation: Invictus IR Cloud Ransomware 2024) Sometimes adversaries may model account names off of those already existing in the system, as a follow-on behavior to Account Discovery. Note that this is distinct from Impersonation, which describes impersonating specific trusted individuals or organizations, rather than user or service account names.

Adversaries may modify a process's in-memory arguments to change its name in order to appear as a legitimate or benign process. On Linux, the operating system stores command-line arguments in the process’s stack and passes them to the `main()` function as the `argv` array. The first element, `argv[0]`, typically contains the process name or path - by default, the command used to actually start the process (e.g., `cat /etc/passwd`). By default, the Linux `/proc` filesystem uses this value to represent the process name. The `/proc/<PID>/cmdline` file reflects the contents of this memory, and tools like `ps` use it to display process information. Since arguments are stored in user-space memory at launch, this modification can be performed without elevated privileges. During runtime, adversaries can erase the memory used by all command-line arguments for a process, overwriting each argument string with null bytes. This removes evidence of how the process was originally launched. They can then write a spoofed string into the memory region previously occupied by `argv[0]` to mimic a benign command, such as `cat resolv.conf`. The new command-line string is reflected in `/proc/<PID>/cmdline` and displayed by tools like `ps`.(Citation: Sandfly BPFDoor 2022)(Citation: Microsoft XorDdos Linux Stealth 2022)

Adversaries may attempt to blend in with legitimate traffic by spoofing browser and system attributes like operating system, system language, platform, user-agent string, resolution, time zone, etc. The HTTP User-Agent request header is a string that lets servers and network peers identify the application, operating system, vendor, and/or version of the requesting user agent.(Citation: Mozilla User Agent) Adversaries may gather this information through System Information Discovery or by users navigating to adversary-controlled websites, and then use that information to craft their web traffic to evade defenses.(Citation: Gummy Browsers: Targeted Browser Spoofing against State-of-the-Art Fingerprinting Techniques)

Adversaries may use scripts automatically executed at boot or logon initialization to establish persistence.(Citation: Mandiant APT29 Eye Spy Email Nov 22)(Citation: Anomali Rocke March 2019) Initialization scripts can be used to perform administrative functions, which may often execute other programs or send information to an internal logging server. These scripts can vary based on operating system and whether applied locally or remotely. Adversaries may use these scripts to maintain persistence on a single system. Depending on the access configuration of the logon scripts, either local credentials or an administrator account may be necessary. An adversary may also be able to escalate their privileges since some boot or logon initialization scripts run with higher privileges.

Adversaries may use Windows logon scripts automatically executed at logon initialization to establish persistence. Windows allows logon scripts to be run whenever a specific user or group of users log into a system.(Citation: TechNet Logon Scripts) This is done via adding a path to a script to the <code>HKCU\Environment\UserInitMprLogonScript</code> Registry key.(Citation: Hexacorn Logon Scripts) Adversaries may use these scripts to maintain persistence on a single system. Depending on the access configuration of the logon scripts, either local credentials or an administrator account may be necessary.

Adversaries may use a Login Hook to establish persistence executed upon user logon. A login hook is a plist file that points to a specific script to execute with root privileges upon user logon. The plist file is located in the <code>/Library/Preferences/com.apple.loginwindow.plist</code> file and can be modified using the <code>defaults</code> command-line utility. This behavior is the same for logout hooks where a script can be executed upon user logout. All hooks require administrator permissions to modify or create hooks.(Citation: Login Scripts Apple Dev)(Citation: LoginWindowScripts Apple Dev) Adversaries can add or insert a path to a malicious script in the <code>com.apple.loginwindow.plist</code> file, using the <code>LoginHook</code> or <code>LogoutHook</code> key-value pair. The malicious script is executed upon the next user login. If a login hook already exists, adversaries can add additional commands to an existing login hook. There can be only one login and logout hook on a system at a time.(Citation: S1 macOs Persistence)(Citation: Wardle Persistence Chapter) **Note:** Login hooks were deprecated in 10.11 version of macOS in favor of Launch Daemon and Launch Agent

Adversaries may use network logon scripts automatically executed at logon initialization to establish persistence. Network logon scripts can be assigned using Active Directory or Group Policy Objects.(Citation: Petri Logon Script AD) These logon scripts run with the privileges of the user they are assigned to. Depending on the systems within the network, initializing one of these scripts could apply to more than one or potentially all systems. Adversaries may use these scripts to maintain persistence on a network. Depending on the access configuration of the logon scripts, either local credentials or an administrator account may be necessary.

Adversaries may establish persistence by modifying RC scripts, which are executed during a Unix-like system’s startup. These files allow system administrators to map and start custom services at startup for different run levels. RC scripts require root privileges to modify. Adversaries may establish persistence by adding a malicious binary path or shell commands to <code>rc.local</code>, <code>rc.common</code>, and other RC scripts specific to the Unix-like distribution.(Citation: IranThreats Kittens Dec 2017)(Citation: Intezer HiddenWasp Map 2019) Upon reboot, the system executes the script's contents as root, resulting in persistence. Adversary abuse of RC scripts is especially effective for lightweight Unix-like distributions using the root user as default, such as ESXi hypervisors, IoT, or embedded systems.(Citation: intezer-kaiji-malware) As ESXi servers store most system files in memory and therefore discard changes on shutdown, leveraging `/etc/rc.local.d/local.sh` is one of the few mechanisms for enabling persistence across reboots.(Citation: Juniper Networks ESXi Backdoor 2022) Several Unix-like systems have moved to Systemd and deprecated the use of RC scripts. This is now a deprecated mechanism in macOS in favor of Launchd.(Citation: Apple Developer Doco Archive Launchd)(Citation: Startup Items) This technique can be used on Mac OS X Panther v10.3 and earlier versions which still execute the RC scripts.(Citation: Methods of Mac Malware Persistence) To maintain backwards compatibility some systems, such as Ubuntu, will execute the RC scripts if they exist with the correct file permissions.(Citation: Ubuntu Manpage systemd rc)

Adversaries may use startup items automatically executed at boot initialization to establish persistence. Startup items execute during the final phase of the boot process and contain shell scripts or other executable files along with configuration information used by the system to determine the execution order for all startup items.(Citation: Startup Items) This is technically a deprecated technology (superseded by Launch Daemon), and thus the appropriate folder, <code>/Library/StartupItems</code> isn’t guaranteed to exist on the system by default, but does appear to exist by default on macOS Sierra. A startup item is a directory whose executable and configuration property list (plist), <code>StartupParameters.plist</code>, reside in the top-level directory. An adversary can create the appropriate folders/files in the StartupItems directory to register their own persistence mechanism.(Citation: Methods of Mac Malware Persistence) Additionally, since StartupItems run during the bootup phase of macOS, they will run as the elevated root user.

Windows systems use a common method to look for required DLLs to load into a program. (Citation: Microsoft DLL Search) 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, (Citation: OWASP Binary Planting) 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. (Citation: Microsoft 2269637) 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. (Citation: Microsoft DLL Redirection) (Citation: Microsoft Manifests) (Citation: Mandiant Search Order) 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.

Adversaries may search network shares on computers they have compromised to find files of interest. Sensitive 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. Interactive command shells may be in use, and common functionality within cmd may be used to gather information.

Adversaries may passively sniff network traffic to capture information about an environment, including authentication material passed over the network. Network sniffing refers to using the network interface on a system to monitor or capture information sent over a wired or wireless connection. An adversary may place a network interface into promiscuous mode to passively access data in transit over the network, or use span ports to capture a larger amount of data. Data captured via this technique may include user credentials, especially those sent over an insecure, unencrypted protocol. Techniques for name service resolution poisoning, such as LLMNR/NBT-NS Poisoning and SMB Relay, can also be used to capture credentials to websites, proxies, and internal systems by redirecting traffic to an adversary. Network sniffing may reveal configuration details, such as running services, version numbers, and other network characteristics (e.g. IP addresses, hostnames, VLAN IDs) necessary for subsequent Lateral Movement and/or Defense Evasion activities. Adversaries may likely also utilize network sniffing during Adversary-in-the-Middle (AiTM) to passively gain additional knowledge about the environment. In cloud-based environments, adversaries may still be able to use traffic mirroring services to sniff network traffic from virtual machines. For example, AWS Traffic Mirroring, GCP Packet Mirroring, and Azure vTap allow users to define specified instances to collect traffic from and specified targets to send collected traffic to.(Citation: AWS Traffic Mirroring)(Citation: GCP Packet Mirroring)(Citation: Azure Virtual Network TAP) Often, much of this traffic will be in cleartext due to the use of TLS termination at the load balancer level to reduce the strain of encrypting and decrypting traffic.(Citation: Rhino Security Labs AWS VPC Traffic Mirroring)(Citation: SpecterOps AWS Traffic Mirroring) The adversary can then use exfiltration techniques such as Transfer Data to Cloud Account in order to access the sniffed traffic.(Citation: Rhino Security Labs AWS VPC Traffic Mirroring) On network devices, adversaries may perform network captures using Network Device CLI commands such as `monitor capture`.(Citation: US-CERT-TA18-106A)(Citation: capture_embedded_packet_on_software)

Adversaries may steal data by exfiltrating it over an existing command and control channel. Stolen data is encoded into the normal communications channel using the same protocol as command and control communications.

When 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 (Citation: Microsoft Change Default Programs) (Citation: Microsoft File Handlers) or by administrators using the built-in assoc utility. (Citation: Microsoft Assoc Oct 2017) 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 <code>HKEY_CLASSES_ROOT\.[extension]</code>, for example <code>HKEY_CLASSES_ROOT\.txt</code>. The entries point to a handler for that extension located at <code>HKEY_CLASSES_ROOT\[handler]</code>. The various commands are then listed as subkeys underneath the shell key at <code>HKEY_CLASSES_ROOT\[handler]\shell\[action]\command</code>. For example: * <code>HKEY_CLASSES_ROOT\txtfile\shell\open\command</code> * <code>HKEY_CLASSES_ROOT\txtfile\shell\print\command</code> * <code>HKEY_CLASSES_ROOT\txtfile\shell\printto\command</code> The values of the keys listed are commands that are executed when the handler opens the file extension. Adversaries can modify these values to continually execute arbitrary commands. (Citation: TrendMicro TROJ-FAKEAV OCT 2012)

**This technique has been deprecated. Please use Non-Standard Port where appropriate.** Adversaries 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)

Processes 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 <code>%TEMP%</code> 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. (Citation: Mozilla Firefox Installer DLL Hijack) (Citation: Seclists Kanthak 7zip Installer)

Software 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, (Citation: Wikipedia Exe Compression) but adversaries may create their own packing techniques that do not leave the same artifacts as well-known packers to evade defenses. Adversaries may use virtual machine software protection as a form of software packing to protect their code. Virtual machine software protection translates an executable's original code into a special format that only a special virtual machine can run. A virtual machine is then called to run this code.(Citation: ESET FinFisher Jan 2018)

Adversaries may attempt to get a listing of services running on remote hosts and local network infrastructure devices, including those that may be vulnerable to remote software exploitation. Common methods to acquire this information include port, vulnerability, and/or wordlist scans using tools that are brought onto a system.(Citation: CISA AR21-126A FIVEHANDS May 2021) Within cloud environments, adversaries may attempt to discover services running on other cloud hosts. Additionally, if the cloud environment is connected to a on-premises environment, adversaries may be able to identify services running on non-cloud systems as well. Within macOS environments, adversaries may use the native Bonjour application to discover services running on other macOS hosts within a network. The Bonjour mDNSResponder daemon automatically registers and advertises a host’s registered services on the network. For example, adversaries can use a mDNS query (such as <code>dns-sd -B _ssh._tcp .</code>) to find other systems broadcasting the ssh service.(Citation: apple doco bonjour description)(Citation: macOS APT Activity Bradley)

Adversaries may abuse Windows Management Instrumentation (WMI) to execute malicious commands and payloads. WMI is designed for programmers and is the infrastructure for management data and operations on Windows systems.(Citation: WMI 1-3) WMI is an administration feature that provides a uniform environment to access Windows system components. The WMI service enables both local and remote access, though the latter is facilitated by Remote Services such as Distributed Component Object Model and Windows Remote Management.(Citation: WMI 1-3) Remote WMI over DCOM operates using port 135, whereas WMI over WinRM operates over port 5985 when using HTTP and 5986 for HTTPS.(Citation: WMI 1-3) (Citation: Mandiant WMI) An adversary can use WMI to interact with local and remote systems and use it as a means to execute various behaviors, such as gathering information for Discovery as well as Execution of commands and payloads.(Citation: Mandiant WMI) For example, `wmic.exe` can be abused by an adversary to delete shadow copies with the command `wmic.exe Shadowcopy Delete` (i.e., Inhibit System Recovery).(Citation: WMI 6) **Note:** `wmic.exe` is deprecated as of January of 2024, with the WMIC feature being “disabled by default” on Windows 11+. WMIC will be removed from subsequent Windows releases and replaced by PowerShell as the primary WMI interface.(Citation: WMI 7,8) In addition to PowerShell and tools like `wbemtool.exe`, COM APIs can also be used to programmatically interact with WMI via C++, .NET, VBScript, etc.(Citation: WMI 7,8)

Adversaries may steal data by exfiltrating it over a different protocol than that of the existing command and control channel. The data may also be sent to an alternate network location from the main command and control server. Alternate protocols include FTP, SMTP, HTTP/S, DNS, SMB, or any other network protocol not being used as the main command and control channel. Adversaries may also opt to encrypt and/or obfuscate these alternate channels. Exfiltration Over Alternative Protocol can be done using various common operating system utilities such as Net/SMB or FTP.(Citation: Palo Alto OilRig Oct 2016) On macOS and Linux <code>curl</code> may be used to invoke protocols such as HTTP/S or FTP/S to exfiltrate data from a system.(Citation: 20 macOS Common Tools and Techniques) Many IaaS and SaaS platforms (such as Microsoft Exchange, Microsoft SharePoint, GitHub, and AWS S3) support the direct download of files, emails, source code, and other sensitive information via the web console or Cloud API.

Adversaries may steal data by exfiltrating it over a symmetrically encrypted network protocol other than that of the existing command and control channel. The data may also be sent to an alternate network location from the main command and control server. Symmetric encryption algorithms are those that use shared or the same keys/secrets on each end of the channel. This requires an exchange or pre-arranged agreement/possession of the value used to encrypt and decrypt data. Network protocols that use asymmetric encryption often utilize symmetric encryption once keys are exchanged, but adversaries may opt to manually share keys and implement symmetric cryptographic algorithms (ex: RC4, AES) vice using mechanisms that are baked into a protocol. This may result in multiple layers of encryption (in protocols that are natively encrypted such as HTTPS) or encryption in protocols that not typically encrypted (such as HTTP or FTP).

Adversaries may steal data by exfiltrating it over an asymmetrically encrypted network protocol other than that of the existing command and control channel. The data may also be sent to an alternate network location from the main command and control server. Asymmetric encryption algorithms are those that use different keys on each end of the channel. Also known as public-key cryptography, this requires pairs of cryptographic keys that can encrypt/decrypt data from the corresponding key. Each end of the communication channels requires a private key (only in the procession of that entity) and the public key of the other entity. The public keys of each entity are exchanged before encrypted communications begin. Network protocols that use asymmetric encryption (such as HTTPS/TLS/SSL) often utilize symmetric encryption once keys are exchanged. Adversaries may opt to use these encrypted mechanisms that are baked into a protocol.

Adversaries may steal data by exfiltrating it over an un-encrypted network protocol other than that of the existing command and control channel. The data may also be sent to an alternate network location from the main command and control server.(Citation: copy_cmd_cisco) Adversaries may opt to obfuscate this data, without the use of encryption, within network protocols that are natively unencrypted (such as HTTP, FTP, or DNS). This may include custom or publicly available encoding/compression algorithms (such as base64) as well as embedding data within protocol headers and fields.

Adversaries 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. An adversary who gains access to a system that is part of a cloud-based environment may map out Virtual Private Clouds or Virtual Networks in order to determine what systems and services are connected. The actions performed are likely the same types of discovery techniques depending on the operating system, but the resulting information may include details about the networked cloud environment relevant to the adversary's goals. Cloud providers may have different ways in which their virtual networks operate.(Citation: Amazon AWS VPC Guide)(Citation: Microsoft Azure Virtual Network Overview)(Citation: Google VPC Overview) Similarly, adversaries who gain access to network devices may also perform similar discovery activities to gather information about connected systems and services. Utilities and commands that acquire this information include netstat, "net use," and "net session" with Net. In Mac and Linux, netstat and <code>lsof</code> can be used to list current connections. <code>who -a</code> and <code>w</code> can be used to show which users are currently logged in, similar to "net session". Additionally, built-in features native to network devices and Network Device CLI may be used (e.g. <code>show ip sockets</code>, <code>show tcp brief</code>).(Citation: US-CERT-TA18-106A) On ESXi servers, the command `esxi network ip connection list` can be used to list active network connections.(Citation: Sygnia ESXi Ransomware 2025)

When operating systems boot up, they can start programs or applications called services that perform background system functions. (Citation: TechNet Services) 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.

**This technique has been deprecated and should no longer be used.** Adversaries 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 (Citation: Microsoft Web Root OCT 2016) (Citation: Apache Server 2018) 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. (Citation: Webroot PHP 2011)

Adversaries may attempt to exfiltrate data via a physical medium, such as a removable drive. In 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.

Adversaries may attempt to exfiltrate data over a USB connected physical device. In certain circumstances, such as an air-gapped network compromise, exfiltration could occur via a USB device introduced by a user. The USB device could be used as the final exfiltration point or to hop between otherwise disconnected systems.

Adversaries may abuse task scheduling functionality to facilitate initial or recurring execution of malicious code. Utilities exist within all major operating systems to schedule programs or scripts to be executed at a specified date and time. A task can also be scheduled on a remote system, provided the proper authentication is met (ex: RPC and file and printer sharing in Windows environments). Scheduling a task on a remote system typically may require being a member of an admin or otherwise privileged group on the remote system.(Citation: TechNet Task Scheduler Security) Adversaries may use task scheduling to execute programs at system startup or on a scheduled basis for persistence. These mechanisms can also be abused to run a process under the context of a specified account (such as one with elevated permissions/privileges). Similar to System Binary Proxy Execution, adversaries have also abused task scheduling to potentially mask one-time execution under a trusted system process.(Citation: ProofPoint Serpent)

Adversaries may abuse the at utility to perform task scheduling for initial, recurring, or future execution of malicious code. The at command within Linux operating systems enables administrators to schedule tasks.(Citation: Kifarunix - Task Scheduling in Linux) An adversary may use at in Linux environments to execute programs at system startup or on a scheduled basis for persistence. at can also be abused to conduct remote Execution as part of Lateral Movement and or to run a process under the context of a specified account. Adversaries may also abuse at to break out of restricted environments by using a task to spawn an interactive system shell or to run system commands. Similarly, at may also be used for Privilege Escalation if the binary is allowed to run as superuser via <code>sudo</code>.(Citation: GTFObins at)

Adversaries may abuse the at utility to perform task scheduling for initial or recurring execution of malicious code. The at utility exists as an executable within Windows, Linux, and macOS for scheduling tasks at a specified time and date. Although deprecated in favor of Scheduled Task's schtasks in Windows environments, using at requires that the Task Scheduler service be running, and the user to be logged on as a member of the local Administrators group. In addition to explicitly running the `at` command, adversaries may also schedule a task with at by directly leveraging the Windows Management Instrumentation `Win32_ScheduledJob` WMI class.(Citation: Malicious Life by Cybereason) On Linux and macOS, at may be invoked by the superuser as well as any users added to the <code>at.allow</code> file. If the <code>at.allow</code> file does not exist, the <code>at.deny</code> file is checked. Every username not listed in <code>at.deny</code> is allowed to invoke at. If the <code>at.deny</code> exists and is empty, global use of at is permitted. If neither file exists (which is often the baseline) only the superuser is allowed to use at.(Citation: Linux at) Adversaries may use at to execute programs at system startup or on a scheduled basis for Persistence. at can also be abused to conduct remote Execution as part of Lateral Movement and/or to run a process under the context of a specified account (such as SYSTEM). In Linux environments, adversaries may also abuse at to break out of restricted environments by using a task to spawn an interactive system shell or to run system commands. Similarly, at may also be used for Privilege Escalation if the binary is allowed to run as superuser via <code>sudo</code>.(Citation: GTFObins at)

Adversaries may abuse the <code>cron</code> utility to perform task scheduling for initial or recurring execution of malicious code.(Citation: 20 macOS Common Tools and Techniques) The <code>cron</code> utility is a time-based job scheduler for Unix-like operating systems. The <code> crontab</code> file contains the schedule of cron entries to be run and the specified times for execution. Any <code>crontab</code> files are stored in operating system-specific file paths. An adversary may use <code>cron</code> in Linux or Unix environments to execute programs at system startup or on a scheduled basis for Persistence. In ESXi environments, cron jobs must be created directly via the crontab file (e.g., `/var/spool/cron/crontabs/root`).(Citation: CloudSEK ESXiArgs 2023)

This technique is deprecated due to the inaccurate usage. The report cited did not provide technical detail as to how the malware interacted directly with launchd rather than going through known services. Other system services are used to interact with launchd rather than launchd being used by itself. Adversaries may abuse the <code>Launchd</code> daemon to perform task scheduling for initial or recurring execution of malicious code. The <code>launchd</code> daemon, native to macOS, is responsible for loading and maintaining services within the operating system. This process loads the parameters for each launch-on-demand system-level daemon from the property list (plist) files found in <code>/System/Library/LaunchDaemons</code> and <code>/Library/LaunchDaemons</code> (Citation: AppleDocs Launch Agent Daemons). These LaunchDaemons have property list files which point to the executables that will be launched (Citation: Methods of Mac Malware Persistence). An adversary may use the <code>launchd</code> daemon in macOS environments to schedule new executables to run at system startup or on a scheduled basis for persistence. <code>launchd</code> can also be abused to run a process under the context of a specified account. Daemons, such as <code>launchd</code>, run with the permissions of the root user account, and will operate regardless of which user account is logged in.

Adversaries may abuse the Windows Task Scheduler to perform task scheduling for initial or recurring execution of malicious code. There are multiple ways to access the Task Scheduler in Windows. The schtasks utility can be run directly on the command line, or the Task Scheduler can be opened through the GUI within the Administrator Tools section of the Control Panel.(Citation: Stack Overflow) In some cases, adversaries have used a .NET wrapper for the Windows Task Scheduler, and alternatively, adversaries have used the Windows netapi32 library and Windows Management Instrumentation (WMI) to create a scheduled task. Adversaries may also utilize the Powershell Cmdlet `Invoke-CimMethod`, which leverages WMI class `PS_ScheduledTask` to create a scheduled task via an XML path.(Citation: Red Canary - Atomic Red Team) An adversary may use Windows Task Scheduler to execute programs at system startup or on a scheduled basis for persistence. The Windows Task Scheduler can also be abused to conduct remote Execution as part of Lateral Movement and/or to run a process under the context of a specified account (such as SYSTEM). Similar to System Binary Proxy Execution, adversaries have also abused the Windows Task Scheduler to potentially mask one-time execution under signed/trusted system processes.(Citation: ProofPoint Serpent) Adversaries may also create "hidden" scheduled tasks (i.e. Hide Artifacts) that may not be visible to defender tools and manual queries used to enumerate tasks. Specifically, an adversary may hide a task from `schtasks /query` and the Task Scheduler by deleting the associated Security Descriptor (SD) registry value (where deletion of this value must be completed using SYSTEM permissions).(Citation: SigmaHQ)(Citation: Tarrask scheduled task) Adversaries may also employ alternate methods to hide tasks, such as altering the metadata (e.g., `Index` value) within associated registry keys.(Citation: Defending Against Scheduled Task Attacks in Windows Environments)

Adversaries may abuse systemd timers to perform task scheduling for initial or recurring execution of malicious code. Systemd timers are unit files with file extension <code>.timer</code> that control services. Timers can be set to run on a calendar event or after a time span relative to a starting point. They can be used as an alternative to Cron in Linux environments.(Citation: archlinux Systemd Timers Aug 2020) Systemd timers may be activated remotely via the <code>systemctl</code> command line utility, which operates over SSH.(Citation: Systemd Remote Control) Each <code>.timer</code> file must have a corresponding <code>.service</code> file with the same name, e.g., <code>example.timer</code> and <code>example.service</code>. <code>.service</code> files are Systemd Service unit files that are managed by the systemd system and service manager.(Citation: Linux man-pages: systemd January 2014) Privileged timers are written to <code>/etc/systemd/system/</code> and <code>/usr/lib/systemd/system</code> while user level are written to <code>~/.config/systemd/user/</code>. An adversary may use systemd timers to execute malicious code at system startup or on a scheduled basis for persistence.(Citation: Arch Linux Package Systemd Compromise BleepingComputer 10JUL2018)(Citation: gist Arch package compromise 10JUL2018)(Citation: acroread package compromised Arch Linux Mail 8JUL2018) Timers installed using privileged paths may be used to maintain root level persistence. Adversaries may also install user level timers to achieve user level persistence.(Citation: Falcon Sandbox smp: 28553b3a9d)