WFP Filter and Provider Changed (Windows Event Log)

Group by: _time, host
Source: github.com/anvilogic-forge/armory

Threat actors may abuse Windows Filtering Platform filters to prevent EDR agents from reporting security events, as observed with tools like EDRSilencer or EDRNoisemaker. This use case detects when a host has events for both WFP provider and filter changes within a short time period (default 30s).

MITRE ATT&CK coverage

Tactic	Techniques
Defense Impairment	`T1685` Disable or Modify Tools

References

Telemetry coverage

Provider	Record / event type
Security-Auditing	Event ID 5447: A Windows Filtering Platform filter has been changed.
Security-Auditing	Event ID 5448: A Windows Filtering Platform provider has been changed.

Rule body

id: '38988.70115'
title: WFP Filter and Provider Changed
description: Threat actors may abuse Windows Filtering Platform filters to prevent
  EDR agents from reporting security events, as observed with tools like EDRSilencer
  or EDRNoisemaker. This use case detects when a host has events for both WFP provider
  and filter changes within a short time period (default 30s).
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=5447) OR
  "<EventID>5447<" OR TERM(EventCode=5448) OR "<EventID>5448<") | regex user!="NT\sAUTHORITY|\$$"
  | table _time, host, user, process, process_*, parent_process_name, user, signature_id
  | bin span=30s | stats values(*) as * by _time, host | where match(signature_id,
  "5447") and match(signature_id, "5448") '
techniques:
- defense-evasion:impair defenses
technique_id: 
- T1562
data_category:
- Windows event logs
references:
- https://github.com/netero1010/EDRSilencer
- https://github.com/amjcyber/EDRNoiseMaker
- https://ghoulsec.medium.com/misc-series-4-forensics-on-edrsilencer-events-428b20b3f983
- https://www.huntress.com/blog/silencing-the-edr-silencers

Stages and Predicates

Stage 1: `search`

`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=5447) OR "<EventID>5447<" OR TERM(EventCode=5448) OR "<EventID>5448<")

Stage 2: `regex`

| regex user!="NT\sAUTHORITY|\$$"

Stage 3: `table`

| table _time, host, user, process, process_*, parent_process_name, user, signature_id

Stage 4: `bucket`

| bin span=30s

Stage 5: `stats`

| stats values(*) as * by _time, host

Stage 6: `where`

| where match(signature_id, "5447") and match(signature_id, "5448")

Exclusions

The rule actively suppresses these predicates.

Field	Kind	Excluded values	Search
`user`	regex_match	`"NT\sAUTHORITY`, `$$"`	`excludes:user`

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`EventCode`	eq	`5447` `5448`	`field:"EventID" kind:eq`
`signature_id`	regex_match	`"5447"` `"5448"`	`field:"signature_id" kind:regex_match`

Search terms

These SPL tokens match against raw event text.

Stage	Term
1	`"<EventID>5447<"`
1	`"<EventID>5448<"`