WFP Filter Added via Registry

Status: experimental
Severity: medium
Log source: category registry_set, product windows
Author: Frack113
Source: github.com/SigmaHQ/sigma

Detects registry modifications that add Windows Filtering Platform (WFP) filters, which may be used to block security tools and EDR agents from reporting events.

MITRE ATT&CK coverage

Tactic	Techniques
Execution	`T1569.002` System Services: Service Execution
Defense Impairment	`T1685` Disable or Modify Tools

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 13: RegistryEvent (Value Set)

Rule body

title: WFP Filter Added via Registry
id: 1f1d8209-636e-4c6c-a137-781cca8b82f9
status: experimental
description: |
    Detects registry modifications that add Windows Filtering Platform (WFP) filters, which may be used to block security tools and EDR agents from reporting events.
references:
    - https://github.com/netero1010/EDRSilencer/blob/0e73a7037ec65c52894d8208e6f605a7da0a34a6/EDRSilencer.c
    - https://www.huntress.com/blog/silencing-the-edr-silencers
    - https://www.trendmicro.com/en_us/research/24/j/edrsilencer-disrupting-endpoint-security-solutions.html
author: Frack113
date: 2025-10-23
tags:
    - attack.execution
    - attack.defense-impairment
    - attack.t1685
    - attack.t1569.002
logsource:
    category: registry_set
    product: windows
detection:
    selection:
        TargetObject|contains: '\BFE\Parameters\Policy\Persistent\Filter\'
    filter_main_svchost:
        Image:
            - 'C:\Windows\System32\svchost.exe'
            - 'C:\Windows\SysWOW64\svchost.exe'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Unknown
level: medium

Stages and Predicates

Stage 0: `condition`

selection and not 1 of filter_main_*

Stage 1: `selection`

selection:
    TargetObject|contains: '\BFE\Parameters\Policy\Persistent\Filter\'

Stage 2: `not filter_main_svchost`

filter_main_svchost:
    Image:
        - 'C:\Windows\System32\svchost.exe'
        - 'C:\Windows\SysWOW64\svchost.exe'

Exclusions

The rule actively suppresses these predicates.

Field	Kind	Excluded values	Search
`Image`	eq	`C:\Windows\SysWOW64\svchost.exe`	`excludes:Image` `field:"Image" value:"C:\Windows\SysWOW64\svchost.exe"`
`Image`	eq	`C:\Windows\System32\svchost.exe`	`excludes:Image` `field:"Image" value:"C:\Windows\System32\svchost.exe"`

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`TargetObject`	match	`\BFE\Parameters\Policy\Persistent\Filter\`	`field:"TargetObject" kind:match value:"\BFE\Parameters\Policy\Persistent\Filter\"`