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Detection rules › Sigma

WerFault LSASS Process Memory Dump

Status
test
Severity
high
Log source
product windows, category file_event
Author
Florian Roth (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects WerFault creating a dump file with a name that indicates that the dump file could be an LSASS process memory, which contains user credentials

MITRE ATT&CK coverage

TacticTechniques
Credential AccessT1003.001 OS Credential Dumping: LSASS Memory

Event coverage

ProviderEventTitle
SysmonEvent ID 11FileCreate

Rule body yaml

title: WerFault LSASS Process Memory Dump
id: c3e76af5-4ce0-4a14-9c9a-25ceb8fda182
status: test
description: Detects WerFault creating a dump file with a name that indicates that the dump file could be an LSASS process memory, which contains user credentials
references:
    - https://github.com/helpsystems/nanodump
author: Florian Roth (Nextron Systems)
date: 2022-06-27
tags:
    - attack.credential-access
    - attack.t1003.001
logsource:
    product: windows
    category: file_event
detection:
    selection:
        Image: C:\WINDOWS\system32\WerFault.exe
        TargetFilename|contains:
            - '\lsass'
            - 'lsass.exe'
    condition: selection
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    Image: C:\WINDOWS\system32\WerFault.exe
    TargetFilename|contains:
        - '\lsass'
        - 'lsass.exe'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Imageeq
  • C:\WINDOWS\system32\WerFault.exe
TargetFilenamematch
  • \lsass corpus 3 (sigma 3)
  • lsass.exe