Overwriting the File with Dev Zero or Null — Sigma Rule

Rule metadata and linked tags

Author: Jakob Weinzettl, oscd.community. Source status: stable; severity: low. Source dates: 2019-10-23 / not supplied.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 52b3ce61990b7ee3a36fa48afbe41f57e7863c2df1152e22fea69b7372e7a22f

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: Overwriting the File with Dev Zero or Null
id: 37222991-11e9-4b6d-8bdf-60fbe48f753e
status: stable
description: Detects overwriting (effectively wiping/deleting) of a file.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1485/T1485.md
author: Jakob Weinzettl, oscd.community
date: 2019-10-23
tags:
    - attack.impact
    - attack.t1485
logsource:
    product: linux
    service: auditd
detection:
    selection:
        type: 'EXECVE'
        a0|contains: 'dd'
        a1|contains:
            - 'if=/dev/null'
            - 'if=/dev/zero'
    condition: selection
falsepositives:
    - Appending null bytes to files.
    - Legitimate overwrite of files.
level: low

Original YAML and metadata in JSON

False positives

• Appending null bytes to files.
• Legitimate overwrite of files.

Source references

• https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1485/T1485.md