huntrule

Possible Decode Base64 Encoded Text -MacOs (via process_creation)

This rule detects use of base64 utility to decode arbitrary base64-encoded text

SigmalowmacOSv1
sigma
title: Possible Decode Base64 Encoded Text -MacOs (via process_creation)
id: 65f0fde4-3d0e-5953-b0ba-6444106bcf78
status: stable
description: This rule detects use of base64 utility to decode arbitrary base64-encoded text
references:
    - https://attack.mitre.org/techniques/T1027/
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1027/T1027.md
author: Huntrule Team
date: 2026-05-12
tags:
    - attack.stealth
    - attack.t1027
logsource:
    category: process_creation
    product: macos
detection:
    selection:
        Image: '/usr/bin/base64'
        CommandLine|contains: '-d'
    condition: selection
falsepositives:
    - Unknown
level: low

Known false positives

  • Unknown

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.