Sigma rule: Suspicious WSL Binary Masquerading

Rule

Title

Suspicious WSL Binary Masquerading

Status

experimental

Level

high

Author

Swachchhanda Shrawan Poudel (Nextron Systems)

Date

2026-05-05

File

rules/windows/process_creation/proc_creation_win_wsl_masquerading.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects execution of masqueraded wsl.exe binary.
Attackers can rename a malicious payload to wsl.exe to masquerade as the legitimate Windows Subsystem for Linux binary,
bypassing detection based on image name alone and abusing user trust in the WSL process name.

Log source

product

windows

category

process_creation

Detection

selection:
    Image|endswith: '\wsl.exe'
filter_main_legit_original:
    OriginalFileName: 'wsl.exe'
filter_main_null:
    OriginalFileName: null
condition: selection and not 1 of filter_main_*

False positives (as the rule lists them)

• Unlikely

Tags

• attack.stealth
• attack.t1036.005
• attack.t1218

MITRE ATT&CK ids this rule names

• T1036.005
• T1218

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_masquerading.yml