blue-team-tools/rules/linux/lnx_binary_padding.yml

title: 'Binary Padding'
id: c52a914f-3d8b-4b2a-bb75-b3991e75f8ba
status: experimental
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.'
  # For this rule to work execve auditing / file system auditing with "execute access" to specific binaries must be configured
  # Example config (place it at the bottom of audit.rules)
  # -a always,exit -F arch=b32 -S execve -k execve
  # -a always,exit -F arch=b64 -S execve -k execve
author: 'Igor Fits, oscd.community'
date: 2020/10/13
references:
  - https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1027.001/T1027.001.md
logsource:
    product: linux
    service: auditd
detection:
    selection1:
        type: 'EXECVE'
        keywords|contains|all:
             - 'truncate'
             - '-s'
    selection2:
        type: 'EXECVE'
        keywords|contains|all:
             - 'dd'
             - 'if='
    filter:
        keywords|contains: 'of='
    condition: selection1 or (selection2 and not filter)
falsepositives:
    - 'Legitimate script work'
level: high
tags:
    - attack.defense_evasion
    - attack.t1027.001