Potential Credential Dumping Activity Via LSASS — Sigma Rule

Rule metadata and linked tags

Author: Samir Bousseaden, Michael Haag. Source status: test; severity: medium. Source dates: 2019-04-03 / 2024-03-02.

{
  "category": "process_access",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 089c24bd4ee1e29da5d6787ef3fca530820003eb0f99bb6f5718060aba6445ba

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: Potential Credential Dumping Activity Via LSASS
id: 5ef9853e-4d0e-4a70-846f-a9ca37d876da
status: test
description: |
    Detects process access requests to the LSASS process with specific call trace calls and access masks.
    This behaviour is expressed by many credential dumping tools such as Mimikatz, NanoDump, Invoke-Mimikatz, Procdump and even the Taskmgr dumping feature.
references:
    - https://web.archive.org/web/20230329170326/https://blog.menasec.net/2019/02/threat-hunting-21-procdump-or-taskmgr.html
    - https://web.archive.org/web/20230208123920/https://cyberwardog.blogspot.com/2017/03/chronicles-of-threat-hunter-hunting-for_22.html
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1003.001/T1003.001.md
    - https://research.splunk.com/endpoint/windows_possible_credential_dumping/
author: Samir Bousseaden, Michael Haag
date: 2019-04-03
modified: 2024-03-02
tags:
    - attack.credential-access
    - attack.t1003.001
    - attack.s0002
logsource:
    category: process_access
    product: windows
detection:
    selection:
        TargetImage|endswith: '\lsass.exe'
        GrantedAccess|contains:
            - '0x1038'
            - '0x1438'
            - '0x143a'
            - '0x1fffff' # Too many false positives
            # - '0x01000'  # Too many false positives
            # - '0x1010'   # Too many false positives
            # - '0x1400'  # Too many false positives
            # - '0x1410' # Too many false positives
            # - '0x40'   # Too many false positives
        CallTrace|contains:
            - 'dbgcore.dll'
            - 'dbghelp.dll'
            - 'kernel32.dll'
            - 'kernelbase.dll'
            - 'ntdll.dll'
    filter_main_system_user:
        SourceUser|contains: # Covers many language settings
            - 'AUTHORI'
            - 'AUTORI'
    filter_optional_thor:
        CallTrace|contains|all:
            - ':\Windows\Temp\asgard2-agent\'
            - '\thor\thor64.exe+'
            - '|UNKNOWN('
        GrantedAccess: '0x103800'
    filter_optional_sysmon:
        SourceImage|endswith: ':\Windows\Sysmon64.exe'
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Unknown
level: medium

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://web.archive.org/web/20230329170326/https://blog.menasec.net/2019/02/threat-hunting-21-procdump-or-taskmgr.html
• https://web.archive.org/web/20230208123920/https://cyberwardog.blogspot.com/2017/03/chronicles-of-threat-hunter-hunting-for_22.html
• https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1003.001/T1003.001.md
• https://research.splunk.com/endpoint/windows_possible_credential_dumping/