Rar Usage with Password and Compression Level — Sigma Rule

Rule metadata and linked tags

Author: @ROxPinTeddy. Source status: test; severity: high. Source dates: 2020-05-12 / 2022-03-16.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: fbbabcb389390efd1728e94af601372010e885c3ffc9f8caaa0d0bfc883b952d

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: Rar Usage with Password and Compression Level
id: faa48cae-6b25-4f00-a094-08947fef582f
status: test
description: Detects the use of rar.exe, on the command line, to create an archive with password protection or with a specific compression level. This is pretty indicative of malicious actions.
references:
    - https://labs.sentinelone.com/the-anatomy-of-an-apt-attack-and-cobaltstrike-beacons-encoded-configuration/
    - https://ss64.com/bash/rar.html
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1560.001/T1560.001.md
author: '@ROxPinTeddy'
date: 2020-05-12
modified: 2022-03-16
tags:
    - attack.collection
    - attack.t1560.001
logsource:
    category: process_creation
    product: windows
detection:
    selection_password:
        CommandLine|contains: ' -hp'
    selection_other:
        CommandLine|contains:
            - ' -m'
            - ' a '
    condition: selection_password and selection_other
falsepositives:
    - Legitimate use of Winrar command line version
    - Other command line tools, that use these flags
level: high

Original YAML and metadata in JSON

False positives

• Legitimate use of Winrar command line version
• Other command line tools, that use these flags

Source references

• https://labs.sentinelone.com/the-anatomy-of-an-apt-attack-and-cobaltstrike-beacons-encoded-configuration/
• https://ss64.com/bash/rar.html
• https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1560.001/T1560.001.md