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Detection rules › Sigma

HackTool - SharpEvtMute Execution

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

Detects the use of SharpEvtHook, a tool that tampers with the Windows event logs

MITRE ATT&CK coverage

TacticTechniques
Defense Impairment

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 1: Process creation

Rule body

title: HackTool - SharpEvtMute Execution
id: bedfc8ad-d1c7-4e37-a20e-e2b0dbee759c
related:
    - id: 49329257-089d-46e6-af37-4afce4290685 # DLL load
      type: similar
status: test
description: Detects the use of SharpEvtHook, a tool that tampers with the Windows event logs
references:
    - https://github.com/bats3c/EvtMute
author: Florian Roth (Nextron Systems)
date: 2022-09-07
modified: 2023-02-14
tags:
    - attack.defense-impairment
    - attack.t1685.001
logsource:
    product: windows
    category: process_creation
detection:
    selection:
        - Image|endswith: '\SharpEvtMute.exe'
        - Description: 'SharpEvtMute'
        - CommandLine|contains:
              - '--Filter "rule '
              - '--Encoded --Filter \"'
    condition: selection
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    - Image|endswith: '\SharpEvtMute.exe'
    - Description: 'SharpEvtMute'
    - CommandLine|contains:
          - '--Filter "rule '
          - '--Encoded --Filter \"'

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
CommandLinematch
  • --Encoded --Filter \"
  • --Filter "rule
field:"CommandLine" kind:match
Descriptioneq
  • SharpEvtMute
field:"Description" kind:eq value:"SharpEvtMute"
Imageends_with
  • \SharpEvtMute.exe
field:"Image" kind:ends_with value:"\SharpEvtMute.exe"