title: Binary Padding - Linux
id: c52a914f-3d8b-4b2a-bb75-b3991e75f8ba
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, oscd.community
date: 2020-10-13
modified: 2023-05-03
tags:
    - attack.stealth
    - attack.t1027.001
logsource:
    product: linux
    service: auditd
detection:
    selection_execve:
        type: 'EXECVE'
    keywords_truncate:
        '|all':
            - 'truncate'
            - '-s'
    keywords_dd:
        '|all':
            - 'dd'
            - 'if='
    keywords_filter:
        - 'of='
    condition: selection_execve and (keywords_truncate or (keywords_dd and not keywords_filter))
falsepositives:
    - Unknown
level: high
simulation:
    - type: atomic-red-team
      name: Pad Binary to Change Hash - Linux/macOS dd
      technique: T1027.001
      atomic_guid: ffe2346c-abd5-4b45-a713-bf5f1ebd573a

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
    - https://linux.die.net/man/1/truncate
    - https://linux.die.net/man/1/dd
author: 'Igor Fits, Mikhail Larin, oscd.community'
date: 2020-10-19
modified: 2023-02-17
tags:
    - attack.stealth
    - attack.t1027.001
logsource:
    product: macos
    category: process_creation
detection:
    selection_truncate:
        Image|endswith: '/truncate'
        CommandLine|contains: '-s +'
    selection_dd:
        Image|endswith: '/dd'
        CommandLine|contains:
            - 'if=/dev/zero' # if input is not /dev/zero, then there is no null padding
            - 'if=/dev/random' # high-quality random data
            - 'if=/dev/urandom' # low-quality random data
    condition: 1 of selection_*
falsepositives:
    - Legitimate script work
level: high

title: Failed Code Integrity Checks
id: 470ec5fa-7b4e-4071-b200-4c753100f49b
status: stable
description: |
    Detects code integrity failures such as missing page hashes or corrupted drivers due unauthorized modification. This could be a sign of tampered binaries.
references:
    - https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-10/security/threat-protection/auditing/event-5038
    - https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-10/security/threat-protection/auditing/event-6281
author: Thomas Patzke
date: 2019-12-03
modified: 2025-01-19
tags:
    - attack.stealth
    - attack.t1027.001
logsource:
    product: windows
    service: security
detection:
    selection:
        EventID:
            - 5038
            - 6281
    filter_optional_crowdstrike:
        param1|contains:
            - '\CSFalconServiceUninstallTool_'
            - '\Program Files\CrowdStrike\'
            - '\System32\drivers\CrowdStrike\'
            - '\Windows\System32\ScriptControl64_'
    filter_optional_sophos:
        param1|contains: '\Program Files\Sophos\'
    condition: selection and not 1 of filter_optional_*
falsepositives:
    - Disk device errors
level: informational