Steganography Unzip Hidden Information From Picture File — Sigma Rule

Rule metadata and linked tags

Author: Pawel Mazur. Source status: test; severity: low. Source dates: 2021-09-09 / 2022-10-09.

{
  "product": "linux",
  "service": "auditd"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: af9dbfe7d5d0b086af9f6b4d9f8d82193b50c94a47ea26c40eea8a21ea08be14

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: Steganography Unzip Hidden Information From Picture File
id: edd595d7-7895-4fa7-acb3-85a18a8772ca
status: test
description: Detects extracting of zip file from image file
references:
    - https://zerotoroot.me/steganography-hiding-a-zip-in-a-jpeg-file/
author: 'Pawel Mazur'
date: 2021-09-09
modified: 2022-10-09
tags:
    - attack.stealth
    - attack.t1027.003
logsource:
    product: linux
    service: auditd
detection:
    commands:
        type: EXECVE
        a0: unzip
    a1:
        a1|endswith:
            - '.jpg'
            - '.png'
    condition: commands and a1
falsepositives:
    - Unknown
level: low

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://zerotoroot.me/steganography-hiding-a-zip-in-a-jpeg-file/