IMPORTANT: No additional bug fixes or documentation updates will be released for this version. For the latest information, see the current release documentation.

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Host Files System Changes via Windows Subsystem for Linux

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Host Files System Changes via Windows Subsystem for Linux

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Detects files creation and modification on the host system from the 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://github.com/microsoft/WSL

Tags:

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

Version: 4

Rule authors:

Elastic

Rule license: Elastic License v2

Rule query

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sequence by process.entity_id with maxspan=5m
 [process where host.os.type == "windows" and event.type == "start" and
  process.name : "dllhost.exe" and
   /* Plan9FileSystem CLSID - WSL Host File System Worker */
  process.command_line : "*{DFB65C4C-B34F-435D-AFE9-A86218684AA8}*"]
 [file where host.os.type == "windows" and process.name : "dllhost.exe" and not file.path : "?:\\Users\\*\\Downloads\\*"]

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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