Detect JavaScript in Microsoft Sentinel
Adversaries may abuse various implementations of JavaScript for execution. JavaScript (JS) is a platform-independent scripting language commonly associated with web pages, but can also execute in runtime environments outside the browser. JScript is Microsoft's implementation interpreted via the Windows Script engine. JavaScript for Automation (JXA) is a macOS scripting language based on JavaScript, included in Apple's Open Scripting Architecture. Adversaries abuse JS for drive-by compromises, malicious email attachments (.js files), HTA-based payloads, and post-exploitation on macOS via JXA. Threat actors including APT32, TA505, Contagious Interview, and FIN6 use JavaScript extensively.
MITRE ATT&CK
- Tactic
- Execution
- Technique
- T1059 Command and Scripting Interpreter
- Sub-technique
- T1059.007 JavaScript
- Canonical reference
- https://attack.mitre.org/techniques/T1059/007/
KQL Detection Query
let SuspiciousPatterns = dynamic([
"WScript.Shell", "Shell.Application",
"Scripting.FileSystemObject", "ADODB.Stream",
"MSXML2.XMLHTTP", "WinHttp.WinHttpRequest",
"ActiveXObject", "new Function",
"eval(", "WScript.CreateObject",
"powershell", "cmd /c", "cmd.exe",
"certutil", "bitsadmin",
"RunHTMLApplication", "javascript:",
"ScriptEngine", "GetObject"
]);
DeviceProcessEvents
| where Timestamp > ago(24h)
| where FileName in~ ("wscript.exe", "cscript.exe", "mshta.exe", "node.exe", "osascript")
| where ProcessCommandLine has_any (SuspiciousPatterns) or ProcessCommandLine has_any (".js", ".jse", ".wsf")
| extend IsJScript = ProcessCommandLine has_any (".js", ".jse") and FileName in~ ("wscript.exe", "cscript.exe")
| extend IsNodeJS = FileName =~ "node.exe"
| extend IsJXA = FileName =~ "osascript" and ProcessCommandLine has "-l JavaScript"
| extend ActiveXUse = ProcessCommandLine has_any ("ActiveXObject", "WScript.CreateObject", "GetObject")
| extend ShellExec = ProcessCommandLine has_any ("WScript.Shell", "Shell.Application", "powershell", "cmd /c")
| project Timestamp, DeviceName, AccountName, FileName, ProcessCommandLine,
InitiatingProcessFileName, InitiatingProcessCommandLine,
IsJScript, IsNodeJS, IsJXA, ActiveXUse, ShellExec
| sort by Timestamp descDetects suspicious JavaScript execution across Windows (JScript via wscript/cscript, Node.js) and macOS (JXA via osascript) using MDE. Identifies ActiveX object creation, shell command execution, and network download patterns common in JavaScript-based malware including SocGholish, Latrodectus, and BlackByte.
Data Sources
Required Tables
False Positives & Tuning
- Developers running Node.js applications on their workstations or servers
- IT automation scripts using JScript/WSF for system administration tasks
- macOS developers using JXA for application automation and testing
- Build systems and CI/CD pipelines that invoke Node.js
Other platforms for T1059.007
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1JScript Execution via wscript.exe
Expected signal: Sysmon Event ID 1: Process Create for wscript.exe executing .js file. Child process event for cmd.exe spawned by wscript.exe. AMSI Event: JScript content inspection.
- Test 2Node.js Command Execution
Expected signal: Sysmon Event ID 1: Process Create for node.exe with child_process in CommandLine. Child process event for cmd.exe spawned by node.exe.
- Test 3JXA Execution on macOS
Expected signal: Unified Log: osascript process with '-l JavaScript' flag. Process tree shows osascript spawning child process for whoami. MDE DeviceProcessEvents on managed macOS endpoints.
References (6)
- https://attack.mitre.org/techniques/T1059/007/
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1059.007/T1059.007.md
- https://nodejs.org/
- https://posts.specterops.io/persistent-jxa-66e1c3cd1cf5
- https://redcanary.com/blog/clipping-silver-sparrows-wings/
- https://lolbas-project.github.io/
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