Windows Binary Executed From WSL

Hunt Hypothesis

Detects the execution of Windows binaries from within a WSL instance. This could be used to masquerade parent-child relationships

Detection Rule

Sigma (Original)

title: Windows Binary Executed From WSL
id: ed825c86-c009-4014-b413-b76003e33d35
status: test
description: |
    Detects the execution of Windows binaries from within a WSL instance.
    This could be used to masquerade parent-child relationships
references:
    - Internal Research
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-02-14
tags:
    - attack.execution
    - attack.stealth
    - attack.t1202
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|re: '[a-zA-Z]:\\'
        CurrentDirectory|contains: '\\\\wsl.localhost' # Note: programs not supporting UNC paths (example: cmd.exe). Will default to another location
    condition: selection
falsepositives:
    - Unknown
level: medium

KQL (Azure Sentinel)

imProcessCreate
| where TargetProcessName matches regex "[a-zA-Z]:\\\\" and TargetProcessCurrentDirectory contains "\\\\wsl.localhost"

Required Data Sources

False Positive Guidance

• Unknown

MITRE ATT&CK Context

• Tactic: Execution
• Technique: T1202 — T1202

References

• Internal Research
• SigmaHQ Rule