Execution via Windows Subsystem for Linux

Detects attempts to execute a program on the host from the Windows Subsystem for Linux. Adversaries may enable and use WSL for Linux to avoid detection.

Rule type: eql

Rule indices:

winlogbeat-*
logs-endpoint.events.*
logs-windows.*
endgame-*

Severity: medium

Risk score: 47

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

https://learn.microsoft.com/en-us/windows/wsl/wsl-config

Tags:

Elastic
Host
Windows
Threat Detection
Defense Evasion
Elastic Endgame

Version: 1

Rule authors:

Elastic

Rule license: Elastic License v2

Rule query

edit

process where event.type : "start" and
 process.parent.executable :
    ("?:\\Windows\\System32\\wsl.exe",
     "?:\\Program Files*\\WindowsApps\\MicrosoftCorporationII.WindowsSubsystemForLinux_*\\wsl.exe",
     "?:\\Windows\\System32\\wslhost.exe",
     "?:\\Program Files*\\WindowsApps\\MicrosoftCorporationII.WindowsSubsystemForLinux_*\\wslhost.exe") and
  not process.executable :
           ("?:\\Windows\\System32\\conhost.exe",
            "?:\\Windows\\System32\\lxss\\wslhost.exe",
            "?:\\Windows\\Sys*\\wslconfig.exe",
            "?:\\Program Files*\\WindowsApps\\MicrosoftCorporationII.WindowsSubsystemForLinux_*\\wsl*.exe",
            "?:\\Windows\\System32\\WerFault.exe",
            "?:\\Program Files\\*",
            "?:\\Program Files (x86)\\*")

Framework: MITRE ATT&CK^TM

Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/
Technique:
- Name: Indirect Command Execution
- ID: T1202
- Reference URL: https://attack.mitre.org/techniques/T1202/

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