Sigma rule: Suspicious WSL InstallLocation Registry Key Modification Via CommandLine

Rule

Title

Suspicious WSL InstallLocation Registry Key Modification Via CommandLine

Status

experimental

Level

high

Author

Swachchhanda Shrawan Poudel (Nextron Systems)

Date

2026-05-05

File

rules/windows/process_creation/proc_creation_win_wsl_installlocation_modification_via_cmdline.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects the use of reg.exe or PowerShell to modify the WSL InstallLocation registry key via command-line arguments.
Legitimate modifications to this key are performed exclusively by the Windows Installer (msiexec.exe) during WSL package installation or update.
Manual use of reg.exe or PowerShell to set this value strongly indicates an attempt to redirect WSL execution to a malicious binary.

Log source

product

windows

category

process_creation

Detection

selection_img:
    - Image|endswith:
          - '\powershell.exe'
          - '\pwsh.exe'
          - '\reg.exe'
    - OriginalFileName:
          - 'powershell.exe'
          - 'pwsh.dll'
          - 'reg.exe'
selection_cli_action:
    CommandLine|contains:
        - ' add '           # reg.exe add subcommand
        - 'New-ItemProperty'
        - 'Set-ItemProperty'
        - 'sp '             # PowerShell alias for Set-ItemProperty
selection_cli_key:
    CommandLine|contains:
        - '\Lxss\MSI'
        - '/Lxss/MSI'       # forward-slash variant sometimes used with PowerShell paths
selection_cli_value:
    CommandLine|contains: 'InstallLocation'
condition: all of selection_*

False positives (as the rule lists them)

• Unlikely

Tags

• attack.stealth
• attack.defense-impairment
• attack.persistence
• attack.t1112
• attack.t1218

MITRE ATT&CK ids this rule names

• T1112
• T1218

Related rules

• 83475063-b1c8-4774-9568-69bbda71a539 (similar)

References

• https://cardinalops.com/blog/bash-and-switch-hijacking-via-windows-subsystem-for-linux/
• https://blog.qualys.com/vulnerabilities-threat-research/2022/04/20/implications-of-windows-subsystem-for-linux-for-adversaries-defenders-part-2
• https://www.bleepingcomputer.com/news/security/new-malware-uses-windows-subsystem-for-linux-for-stealthy-attacks/
• https://thehackernews.com/2021/09/new-malware-targets-windows-subsystem.html
• https://learn.microsoft.com/en-us/windows/wsl/

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/process_creation/proc_creation_win_wsl_installlocation_modification_via_cmdline.yml