Potential Credential Dumping Via WER — Sigma Rule

Rule metadata and linked tags

Author: @pbssubhash , Nasreddine Bencherchali. Source status: test; severity: high. Source dates: 2022-12-08 / 2022-12-09.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 437f66f2de963fcdf7f500c287a3cc5e771c3b9c86f917f0b616ac3e904cab7d

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 Via WER
id: 9a4ccd1a-3526-4d99-b980-9f9c5d3a6ff3
status: test
description: Detects potential credential dumping via Windows Error Reporting LSASS Shtinkering technique which uses the Windows Error Reporting to dump lsass
references:
    - https://github.com/deepinstinct/Lsass-Shtinkering
    - https://media.defcon.org/DEF%20CON%2030/DEF%20CON%2030%20presentations/Asaf%20Gilboa%20-%20LSASS%20Shtinkering%20Abusing%20Windows%20Error%20Reporting%20to%20Dump%20LSASS.pdf
author: '@pbssubhash , Nasreddine Bencherchali'
date: 2022-12-08
modified: 2022-12-09
tags:
    - attack.credential-access
    - attack.t1003.001
logsource:
    product: windows
    category: process_creation
detection:
    selection_img:
        - Image|endswith: '\Werfault.exe'
        - OriginalFileName: 'WerFault.exe'
    selection_cli:
        ParentUser|contains: # covers many language settings
            - 'AUTHORI'
            - 'AUTORI'
        User|contains:
            - 'AUTHORI'
            - 'AUTORI'
        CommandLine|contains|all:
            # Doc: WerFault.exe -u -p <target process> -ip <source process> -s <file mapping handle>
            # Example: C:\Windows\system32\Werfault.exe -u -p 744 -ip 1112 -s 244
            # If the source process is not equal to the target process and the target process is LSASS then this is an indication of this technique
            # Example: If the "-p" points the PID of "lsass.exe" and "-ip" points to a different process than "lsass.exe" then this is a sign of malicious activity
            - ' -u -p '
            - ' -ip '
            - ' -s '
    filter_lsass:
        ParentImage: 'C:\Windows\System32\lsass.exe'
    condition: all of selection_* and not 1 of filter_*
falsepositives:
    - Windows Error Reporting might produce similar behavior. In that case, check the PID associated with the "-p" parameter in the CommandLine.
level: high

Original YAML and metadata in JSON

False positives

• Windows Error Reporting might produce similar behavior. In that case, check the PID associated with the "-p" parameter in the CommandLine.

Source references

• https://github.com/deepinstinct/Lsass-Shtinkering
• https://media.defcon.org/DEF%20CON%2030/DEF%20CON%2030%20presentations/Asaf%20Gilboa%20-%20LSASS%20Shtinkering%20Abusing%20Windows%20Error%20Reporting%20to%20Dump%20LSASS.pdf