Shell Execution GCC - Linux — Sigma Rule

Rule metadata and linked tags

Author: Li Ling, Andy Parkidomo, Robert Rakowski, Blake Hartstein (Bloomberg L.P.). Source status: test; severity: high. Source dates: 2024-09-02 / not supplied.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: f9ecc685a401ff181227570f25997aa17f4faa184437ff8948cb29d2c7063669

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: Shell Execution GCC  - Linux
id: 9b5de532-a757-4d70-946c-1f3e44f48b4d
status: test
description: |
    Detects the use of the "gcc" utility to execute a shell. Such behavior may be associated with privilege escalation, unauthorized command execution, or to break out from restricted environments.
references:
    - https://gtfobins.github.io/gtfobins/gcc/#shell
    - https://gtfobins.github.io/gtfobins/c89/#shell
    - https://gtfobins.github.io/gtfobins/c99/#shell
    - https://www.elastic.co/guide/en/security/current/linux-restricted-shell-breakout-via-linux-binary-s.html
author: Li Ling, Andy Parkidomo, Robert Rakowski, Blake Hartstein (Bloomberg L.P.)
date: 2024-09-02
tags:
    - attack.discovery
    - attack.t1083
logsource:
    category: process_creation
    product: linux
detection:
    selection_img:
        Image|endswith:
            - '/c89'
            - '/c99'
            - '/gcc'
        CommandLine|contains: '-wrapper'
    selection_cli:
        CommandLine|contains:
            - '/bin/bash,-s'
            - '/bin/dash,-s'
            - '/bin/fish,-s'
            - '/bin/sh,-s'
            - '/bin/zsh,-s'
    condition: all of selection_*
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://gtfobins.github.io/gtfobins/gcc/#shell
• https://gtfobins.github.io/gtfobins/c89/#shell
• https://gtfobins.github.io/gtfobins/c99/#shell
• https://www.elastic.co/guide/en/security/current/linux-restricted-shell-breakout-via-linux-binary-s.html