Sigma Rule Library

Potential Credential Dumping Activity Via LSASS

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.

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Detection logic

selection

TargetImage|endswith: \lsass.exe
GrantedAccess|contains:
  - "0x1038"
  - "0x1438"
  - "0x143a"
  - "0x1fffff"
CallTrace|contains:
  - dbgcore.dll
  - dbghelp.dll
  - kernel32.dll
  - kernelbase.dll
  - ntdll.dll

filter_main_system_user

SourceUser|contains:
  - 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
  - :\Windows\Sysmon64a.exe

Condition

selection and not 1 of filter_main_* and not 1 of filter_optional_*

Raw YAML

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: 2026-06-29
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'
            - ':\Windows\Sysmon64a.exe'
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Unknown
level: medium

False positives

  • Unknown

References

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