Sigma rule: Indirect Command Execution From Script File Via Bash.EXE

Rule

Title

Indirect Command Execution From Script File Via Bash.EXE

Status

test

Level

medium

Author

Nasreddine Bencherchali (Nextron Systems)

Date

2023-08-15

File

rules/windows/process_creation/proc_creation_win_bash_file_execution.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects execution of Microsoft bash launcher without any flags to execute the content of a bash script directly.
This can be used to potentially bypass defenses and execute Linux or Windows-based binaries directly via bash.

Log source

product

windows

category

process_creation

Detection

selection:
    - Image|endswith:
          - ':\Windows\System32\bash.exe'
          - ':\Windows\SysWOW64\bash.exe'
    - OriginalFileName: 'Bash.exe'
filter_main_cli_flag:
    CommandLine|contains:
        # Note: we're not interested in flags being passed first
        - 'bash.exe -'
        - 'bash -'
filter_main_no_cli:
    CommandLine: null
filter_main_empty:
    CommandLine: ''
filter_main_no_flag:
    CommandLine:
        - 'bash.exe'
        - 'bash'
condition: selection and not 1 of filter_main_*

False positives (as the rule lists them)

• Unknown

Tags

• attack.stealth
• attack.t1202

MITRE ATT&CK ids this rule names

• T1202

Related rules

• 5edc2273-c26f-406c-83f3-f4d948e740dd (similar)

References

• https://lolbas-project.github.io/lolbas/Binaries/Bash/
• https://linux.die.net/man/1/bash
• Internal Research

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_bash_file_execution.yml