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Detection rules › Sigma

Windows Binary Executed From WSL

Status
test
Severity
medium
Log source
category process_creation, product windows
Author
Nasreddine Bencherchali (Nextron Systems)
Source
github.com/SigmaHQ/sigma

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

MITRE ATT&CK coverage

TacticTechniques
Stealth

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 1: Process creation

Rule body

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

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    Image|re: '[a-zA-Z]:\\'
    CurrentDirectory|contains: '\\\\wsl.localhost'

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
CurrentDirectorymatch
  • \\\\wsl.localhost
field:"CurrentDirectory" kind:match value:"\\\\wsl.localhost"
Imageregex_match
  • [a-zA-Z]:\
field:"Image" kind:regex_match value:"[a-zA-Z]:\"