Detection rules › Sigma

PowerShell Write-EventLog Usage

Status
test
Severity
medium
Log source
product windows, category ps_script
Author
Nasreddine Bencherchali (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects usage of the "Write-EventLog" cmdlet with 'RawData' flag. The cmdlet can be levreage to write malicious payloads to the EventLog and then retrieve them later for later use

MITRE ATT&CK coverage

TacticTechniques
Defense ImpairmentNo specific technique

Event coverage

Rule body yaml

title: PowerShell Write-EventLog Usage
id: 35f41cd7-c98e-469f-8a02-ec4ba0cc7a7e
status: test
description: Detects usage of the "Write-EventLog" cmdlet with 'RawData' flag. The cmdlet can be levreage to write malicious payloads to the EventLog and then retrieve them later for later use
references:
    - https://www.blackhillsinfosec.com/windows-event-logs-for-red-teams/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-08-16
tags:
    - attack.defense-impairment
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection:
        ScriptBlockText|contains|all:
            - 'Write-EventLog'
            - '-RawData '
    condition: selection
falsepositives:
    - Legitimate applications writing events via this cmdlet. Investigate alerts to determine if the action is benign
level: medium

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    ScriptBlockText|contains|all:
        - 'Write-EventLog'
        - '-RawData '

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
ScriptBlockTextmatch
  • -RawData
  • Write-EventLog