Decode Base64 Encoded Text -MacOs — Sigma Rule

Rule metadata and linked tags

Author: Daniil Yugoslavskiy, oscd.community. Source status: test; severity: low. Source dates: 2020-10-19 / 2022-11-26.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 795592ecb08c30766043d1e218078060c9b7c1d802ad5cc14b3e423b610ef34e

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: Decode Base64 Encoded Text -MacOs
id: 719c22d7-c11a-4f2c-93a6-2cfdd5412f68
status: test
description: Detects usage of base64 utility to decode arbitrary base64-encoded text
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1027/T1027.md
author: Daniil Yugoslavskiy, oscd.community
date: 2020-10-19
modified: 2022-11-26
tags:
    - attack.stealth
    - attack.t1027
logsource:
    category: process_creation
    product: macos
detection:
    selection:
        Image: '/usr/bin/base64'
        CommandLine|contains: '-d'
    condition: selection
falsepositives:
    - Legitimate activities
level: low

Original YAML and metadata in JSON

False positives

• Legitimate activities

Source references

• https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1027/T1027.md