blue-team-tools/rules/macos/process_creation/proc_creation_macos_binary_padding.yml

title: Binary Padding - MacOS
id: 95361ce5-c891-4b0a-87ca-e24607884a96
status: test
description: Adversaries may use binary padding to add junk data and change the on-disk representation of malware. This rule detect using dd and truncate to add a junk data to file.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1027.001/T1027.001.md
author: 'Igor Fits, Mikhail Larin, oscd.community'
date: 2020/10/19
modified: 2022/11/26
tags:
    - attack.defense_evasion
    - attack.t1027.001
logsource:
    product: macos
    category: process_creation
detection:
    selection1:
        Image|endswith: '/truncate'
        CommandLine|contains: '-s'
    selection2:
        Image|endswith: '/dd'
        CommandLine|contains: 'if='
    filter:
        CommandLine|contains: 'of='
    condition: selection1 or (selection2 and not filter)
falsepositives:
    - Legitimate script work
level: high