Execution via Windows Subsystem for Linux

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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.process-*
  • logs-windows.*
  • endgame-*
  • logs-system.security*

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:

Tags:

  • Domain: Endpoint
  • OS: Windows
  • Use Case: Threat Detection
  • Tactic: Defense Evasion
  • Data Source: Elastic Endgame
  • Data Source: Elastic Defend

Version: 6

Rule authors:

  • Elastic

Rule license: Elastic License v2

Rule query

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

Framework: MITRE ATT&CKTM