LSASS Access From Non System Account — Sigma Rule

Rule metadata and linked tags

Author: Roberto Rodriguez @Cyb3rWard0g. Source status: test; severity: medium. Source dates: 2019-06-20 / 2023-12-11.

{
  "product": "windows",
  "service": "security"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 65863c05f45751125c9b61f051edf65bbebfb9d055a6dc695553bdc27dadda15

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: LSASS Access From Non System Account
id: 962fe167-e48d-4fd6-9974-11e5b9a5d6d1
status: test
description: Detects potential mimikatz-like tools accessing LSASS from non system account
references:
    - https://threathunterplaybook.com/hunts/windows/170105-LSASSMemoryReadAccess/notebook.html
author: Roberto Rodriguez @Cyb3rWard0g
date: 2019-06-20
modified: 2023-12-11
tags:
    - attack.credential-access
    - attack.t1003.001
logsource:
    product: windows
    service: security
detection:
    selection:
        EventID:
            - 4663
            - 4656
        AccessMask:
            - '0x100000'
            - '0x1010'    # car.2019-04-004
            - '0x1400'
            - '0x1410'    # car.2019-04-004
            - '0x1418'    # car.2019-04-004
            - '0x1438'    # car.2019-04-004
            - '0x143a'    # car.2019-04-004
            - '0x1f0fff'
            - '0x1f1fff'
            - '0x1f2fff'
            - '0x1f3fff'
            - '0x40'
            - '143a'    # car.2019-04-004
            - '1f0fff'
            - '1f1fff'
            - '1f2fff'
            - '1f3fff'
            # - '0x1000'  # minimum access requirements to query basic info from service
        ObjectType: 'Process'
        ObjectName|endswith: '\lsass.exe'
    filter_main_service_account:
        SubjectUserName|endswith: '$'
    filter_main_generic:
        ProcessName|contains:
            # Legitimate AV and EDR solutions
            - ':\Program Files\'
            - ':\Program Files (x86)\'
    filter_main_wmiprvse:
        ProcessName: 'C:\Windows\System32\wbem\WmiPrvSE.exe'
        AccessMask: '0x1410'
    filter_optional_steam:
        ProcessName|contains: '\SteamLibrary\steamapps\'
    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://threathunterplaybook.com/hunts/windows/170105-LSASSMemoryReadAccess/notebook.html