Ruby Inline Command Execution — Sigma Rule

Rule metadata and linked tags

Author: Nasreddine Bencherchali (Nextron Systems). Source status: test; severity: medium. Source dates: 2023-01-02 / not supplied.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: b29d9180dd4a46e0c8cb9f4ad2e4558ba9547626691a8cb89de430d367696d65

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: Ruby Inline Command Execution
id: 20a5ffa1-3848-4584-b6f8-c7c7fd9f69c8
status: test
description: Detects execution of ruby using the "-e" flag. This is could be used as a way to launch a reverse shell or execute live ruby code.
references:
    - https://pentestmonkey.net/cheat-sheet/shells/reverse-shell-cheat-sheet
    - https://www.revshells.com/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-01-02
tags:
    - attack.execution
    - attack.t1059
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\ruby.exe'
        - OriginalFileName: 'ruby.exe'
    selection_cli:
        CommandLine|contains: ' -e'
    condition: all of selection_*
falsepositives:
    - Unknown
level: medium

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://pentestmonkey.net/cheat-sheet/shells/reverse-shell-cheat-sheet
• https://www.revshells.com/