Command and Scripting Interpreter: JavaScript

Adversaries may abuse various implementations of JavaScript for execution. JavaScript (JS) is a platform-independent scripting language (compiled just-in-time at runtime) commonly associated with scripts in webpages, though JS can be executed in runtime environments outside the browser.[1]

JScript is the Microsoft implementation of the same scripting standard. JScript is interpreted via the Windows Script engine and thus integrated with many components of Windows such as the Component Object Model and Internet Explorer HTML Application (HTA) pages.[2][3][4]

JavaScript for Automation (JXA) is a macOS scripting language based on JavaScript, included as part of Apple’s Open Scripting Architecture (OSA), that was introduced in OSX 10.10. Apple’s OSA provides scripting capabilities to control applications, interface with the operating system, and bridge access into the rest of Apple’s internal APIs. As of OSX 10.10, OSA only supports two languages, JXA and AppleScript. Scripts can be executed via the command line utility osascript, they can be compiled into applications or script files via osacompile, and they can be compiled and executed in memory of other programs by leveraging the OSAKit Framework.[5][6][7][8][9]

Adversaries may abuse various implementations of JavaScript to execute various behaviors. Common uses include hosting malicious scripts on websites as part of a Drive-by Compromise or downloading and executing these script files as secondary payloads. Since these payloads are text-based, it is also very common for adversaries to obfuscate their content as part of Obfuscated Files or Information.

ID: T1059.007
Sub-technique of:  T1059
Tactic: Execution
Platforms: Linux, Windows, macOS
Permissions Required: Administrator, SYSTEM, User
Contributors: Cody Thomas, SpecterOps
Version: 2.1
Created: 23 June 2020
Last Modified: 16 August 2021
Provided by LAYER 8

Procedure Examples

ID Name Description
S0622 AppleSeed

AppleSeed has the ability to use JavaScript to execute PowerShell.[10]

G0050 APT32

APT32 has used JavaScript for drive-by downloads and C2 communications.[11][12]

S0373 Astaroth

Astaroth uses JavaScript to perform its core functionalities. [13][14]

S0640 Avaddon

Avaddon has been executed through a malicious JScript downloader.[15][16]

S0482 Bundlore

Bundlore can execute JavaScript by injecting it into the victim's browser.[17]

S0631 Chaes

Chaes has used JavaScript and Node.Js information stealer script that exfiltrates data using the node process.[18]

G0080 Cobalt Group

Cobalt Group has executed JavaScript scriptlets on the victim's machine.[19][20][21][22][23][24]

S0154 Cobalt Strike

The Cobalt Strike System Profiler can use JavaScript to perform reconnaissance actions.[25]

S0634 EnvyScout

EnvyScout can write files to disk with JavaScript using a modified version of the open-source tool FileSaver.[26]

G0120 Evilnum

Evilnum has used malicious JavaScript files on the victim's machine.[27]

G0037 FIN6

FIN6 has used malicious JavaScript to steal payment card data from e-commerce sites.[28]

G0046 FIN7

FIN7 used JavaScript scripts to help perform tasks on the victim's machine.[29][30][29]


GRIFFON is written in and executed as JavaScript.[31]

G0126 Higaisa

Higaisa used JavaScript to execute additional files.[32][33][34]

G0119 Indrik Spider

Indrik Spider has used malicious JavaScript files for several components of their attack.[35]

S0260 InvisiMole

InvisiMole can use a JavaScript file as part of its execution chain.[36]

S0283 jRAT

jRAT has been distributed as HTA files with JScript.[37]

S0648 JSS Loader

JSS Loader can download and execute JavaScript files.[38]

G0094 Kimsuky

Kimsuky has used JScript for logging and downloading additional tools.[39][40]

G0077 Leafminer

Leafminer infected victims using JavaScript code.[41]

S0455 Metamorfo

Metamorfo includes payloads written in JavaScript.[42]

G0021 Molerats

Molerats used various implants, including those built with JS, on target machines.[43]

G0069 MuddyWater

MuddyWater has used JavaScript files to execute its POWERSTATS payload.[44][45]

S0228 NanHaiShu

NanHaiShu executes additional Jscript code on the victim's machine.[46]


POWERSTATS can use JavaScript code for execution.[44]

S0650 QakBot

The QakBot web inject module can inject Java Script into web banking pages visited by the victim.[47]

G0121 Sidewinder

Sidewinder has used JavaScript to drop and execute malware loaders.[48][49]

G0091 Silence

Silence has used JS scripts.[50]

S0646 SpicyOmelette

SpicyOmelette has the ability to execute arbitrary JavaScript code on a compromised host.[51]

G0092 TA505

TA505 has used JavaScript for code execution.[52][53]

G0010 Turla

Turla has used various JavaScript-based backdoors.[54]

S0476 Valak

Valak can execute JavaScript containing configuration data for establishing persistence.[55]

S0341 Xbash

Xbash can execute malicious JavaScript payloads on the victim’s machine.[56]


ID Mitigation Description
M1040 Behavior Prevention on Endpoint

On Windows 10, enable Attack Surface Reduction (ASR) rules to prevent JavaScript scripts from executing potentially malicious downloaded content [57].

M1042 Disable or Remove Feature or Program

Turn off or restrict access to unneeded scripting components.

M1038 Execution Prevention

Denylist scripting where appropriate.

M1021 Restrict Web-Based Content

Script blocking extensions can help prevent the execution of JavaScript and HTA files that may commonly be used during the exploitation process. For malicious code served up through ads, adblockers can help prevent that code from executing in the first place.


ID Data Source Data Component
DS0017 Command Command Execution
DS0011 Module Module Load
DS0009 Process Process Creation
DS0012 Script Script Execution

Monitor for events associated with scripting execution, such as process activity, usage of the Windows Script Host (typically cscript.exe or wscript.exe), file activity involving scripts, or loading of modules associated with scripting languages (ex: JScript.dll). Scripting execution is likely to perform actions with various effects on a system that may generate events, depending on the types of monitoring used. Monitor processes and command-line arguments for execution and subsequent behavior. Actions may be related to network and system information Discovery, Collection, or other programmable post-compromise behaviors and could be used as indicators of detection leading back to the source.

Monitor for execution of JXA through osascript and usage of OSAScript API that may be related to other suspicious behavior occurring on the system.

Understanding standard usage patterns is important to avoid a high number of false positives. If scripting is restricted for normal users, then any attempts to enable related components running on a system would be considered suspicious. If scripting is not commonly used on a system, but enabled, execution running out of cycle from patching or other administrator functions is suspicious. Scripts should be captured from the file system when possible to determine their actions and intent.


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