Indirect Inline Command Execution Via Bash.EXE — Sigma Rule

Rule metadata and linked tags

Author: frack113. Source status: test; severity: medium. Source dates: 2021-11-24 / 2023-08-15.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: a5c65a1d1512052f617a0b1ebffdff80cd17feb7308ba3f024eefda0684de181

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Indirect Inline Command Execution Via Bash.EXE
id: 5edc2273-c26f-406c-83f3-f4d948e740dd
related:
    - id: 2d22a514-e024-4428-9dba-41505bd63a5b
      type: similar
status: test
description: |
    Detects execution of Microsoft bash launcher with the "-c" flag.
    This can be used to potentially bypass defenses and execute Linux or Windows-based binaries directly via bash.
references:
    - https://lolbas-project.github.io/lolbas/Binaries/Bash/
author: frack113
date: 2021-11-24
modified: 2023-08-15
tags:
    - attack.stealth
    - attack.t1202
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith:
              - ':\Windows\System32\bash.exe'
              - ':\Windows\SysWOW64\bash.exe'
        - OriginalFileName: 'Bash.exe'
    selection_cli:
        CommandLine|contains: ' -c '
    condition: all of selection_*
falsepositives:
    - Unknown
level: medium

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://lolbas-project.github.io/lolbas/Binaries/Bash/