Interactive Bash Suspicious Children

SIGMA detection rule by Florian Roth (Nextron Systems) · NOASSERTION

Detects suspicious interactive bash as a parent to rather uncommon child processes

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

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

11432374-b69b-4b7d-9d80-5d8ec8dde4a0

Propose edits, view related rules, and engage with the community through comments.

Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

Rejected pattern present

[[ reason ]]

What does this mean?

Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

[[ reason ]]

What do these messages mean?

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

[[ currentRule.title ]]

Community Discussion