Remove Immutable File Attribute — Sigma Rule

Rule metadata and linked tags

Author: Nasreddine Bencherchali (Nextron Systems). Source status: test; severity: medium. Source dates: 2022-09-15 / not supplied.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 3fbd0d310cba0f7fbfb0d1ca241d20bb8c8f5f43799c45723830f9aa8fb320f4

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: Remove Immutable File Attribute
id: 34979410-e4b5-4e5d-8cfb-389fdff05c12
related:
    - id: a5b977d6-8a81-4475-91b9-49dbfcd941f7
      type: derived
status: test
description: Detects usage of the 'chattr' utility to remove immutable file attribute.
references:
    - https://www.trendmicro.com/en_us/research/22/i/how-malicious-actors-abuse-native-linux-tools-in-their-attacks.html
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-09-15
tags:
    - attack.defense-impairment
    - attack.t1222.002
logsource:
    product: linux
    category: process_creation
detection:
    selection:
        Image|endswith: '/chattr'
        CommandLine|contains: ' -i '
    condition: selection
falsepositives:
    - Administrator interacting with immutable files (e.g. for instance backups).
level: medium

Original YAML and metadata in JSON

False positives

• Administrator interacting with immutable files (e.g. for instance backups).

Source references

• https://www.trendmicro.com/en_us/research/22/i/how-malicious-actors-abuse-native-linux-tools-in-their-attacks.html