Interactive Bash Suspicious Children — Sigma Rule

Rule metadata and linked tags

Author: Florian Roth (Nextron Systems). Source status: test; severity: medium. Source dates: 2022-03-14 / not supplied.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: f4dbbac43bea29f6a68822eeb7e289c8e2fe22fc831ed6047b69d593f008407e

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: Interactive Bash Suspicious Children
id: ea3ecad2-db86-4a89-ad0b-132a10d2db55
status: test
description: Detects suspicious interactive bash as a parent to rather uncommon child processes
references:
    - Internal Research
author: Florian Roth (Nextron Systems)
date: 2022-03-14
tags:
    - attack.execution
    - attack.stealth
    - attack.t1059.004
    - attack.t1036
logsource:
    product: linux
    category: process_creation
detection:
    selection:
        ParentCommandLine: 'bash -i'
    anomaly1:
        CommandLine|contains:
            - '-c import '
            - 'base64'
            - 'pty.spawn'
    anomaly2:
        Image|endswith:
            - 'whoami'
            - 'iptables'
            - '/ncat'
            - '/nc'
            - '/netcat'
    condition: selection and 1 of anomaly*
falsepositives:
    - Legitimate software that uses these patterns
level: medium

Original YAML and metadata in JSON

False positives

• Legitimate software that uses these patterns

Source references

• Internal Research (source note; no public URL supplied)