Detection: Windows Filtering Platform Policy Added to Block EDR Process

Updated Date: 2026-04-13 ID: 1dea4856-f096-4e9d-9bd3-22c568dac5fe Author: Raven Tait, Splunk Type: TTP Product: Splunk Enterprise Security

Description

Detects the modification of a Windows Filtering Platform Policy to block the communication of known EDR processes. This can be used by attackers to impair the functionality of these tools and to hide their activities on the machine.

Search

 1
 2| tstats `security_content_summariesonly`
 3  count min(_time) as firstTime
 4        max(_time) as lastTime
 5
 6from datamodel=Endpoint.Registry where
 7
 8Registry.action="modified"
 9Registry.registry_path="*\\Parameters\\FirewallPolicy\\FirewallRules*"
10Registry.registry_value_data="*Action=Block*"
11Registry.registry_value_data="*App=*"
12Registry.registry_value_data IN (
13    "*AmSvc.exe*",
14    "*cb.exe*",
15    "*CETASvc.exe*",
16    "*CNTAoSMgr.exe*",
17    "*CrAmTray.exe*",
18    "*CrsSvc.exe*",
19    "*CybereasonAV.exe*",
20    "*CylanceSvc.exe*",
21    "*cyserver.exe*",
22    "*CyveraService.exe*",
23    "*CyvrFsFlt.exe*",
24    "*EIConnector.exe*",
25    "*ekrn.exe*",
26    "*elastic-agent.exe*",
27    "*elastic-endpoint.exe*",
28    "*EndpointBasecamp.exe*",
29    "*ExecutionPreventionSvc.exe*",
30    "*filebeat.exe*",
31    "*fortiedr.exe*",
32    "*hurukai.exe*",
33    "*LogProcessorService.exe*",
34    "*MsMpEng.exe*",
35    "*MsSense.exe*",
36    "*Ntrtscan.exe*",
37    "*PccNTMon.exe*",
38    "*QualysAgent.exe*",
39    "*RepMgr.exe*",
40    "*RepUtils.exe*",
41    "*RepUx.exe*",
42    "*RepWAV.exe*",
43    "*RepWSC.exe*",
44    "*SenseCncProxy.exe*",
45    "*SenseIR.exe*",
46    "*SenseNdr.exe*",
47    "*SenseSampleUploader.exe*",
48    "*SentinelAgent.exe*",
49    "*SentinelAgentWorker.exe*",
50    "*SentinelBrowserNativeHost.exe*",
51    "*SentinelHelperService.exe*",
52    "*SentinelServiceHost.exe*",
53    "*SentinelStaticEngine.exe*",
54    "*SentinelStaticEngineScanner.exe*",
55    "*sfc.exe*",
56    "*TaniumClient.exe*",
57    "*TaniumCX.exe*",
58    "*TaniumDetectEngine.exe*",
59    "*TMBMSRV.exe*",
60    "*TmCCSF.exe*",
61    "*TmListen.exe*",
62    "*TmWSCSvc.exe*",
63    "*Traps.exe*",
64    "*winlogbeat.exe*",
65    "*WSCommunicator.exe*",
66    "*xagt.exe*"
67)
68
69by Registry.dest Registry.vendor_product Registry.user Registry.status
70   Registry.registry_value_name Registry.registry_path Registry.registry_hive
71   Registry.registry_value_data Registry.action Registry.process_path
72   Registry.process_guid Registry.process_id Registry.registry_key_name
73
74
75| `drop_dm_object_name(Registry)`
76
77| `security_content_ctime(firstTime)`
78
79| `security_content_ctime(lastTime)`
80
81| `windows_filtering_platform_policy_added_to_block_edr_process_filter`

Data Source

Name	Platform	Sourcetype	Source
Sysmon EventID 13	Windows	`'XmlWinEventLog'`	`'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'`

Macros Used

Name	Value
security_content_ctime	`convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)`
windows_filtering_platform_policy_added_to_block_edr_process_filter	`search *`

windows_filtering_platform_policy_added_to_block_edr_process_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1685	Disable or Modify Tools	Defense Impairment

Exploitation

DE.CM

CIS 10

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Notable	Yes
Rule Title	`%name%`
Rule Description	`%description%`
Notable Event Fields	user, dest
Creates Risk Event	True

This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the Processes node of the Endpoint data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.

Known False Positives

Some legitimate administrative tasks or security configurations may create filtering platform policies. Verify actions with authorized IT personnel before alerting.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

Suspicious Windows Filtering Platform Policy with value $registry_value_data$ created on $dest$.

Risk Object	Risk Object Type	Risk Score	Threat Objects
dest	system	50	registry_path, registry_value_name

References

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`XmlWinEventLog:Microsoft-Windows-Sysmon/Operational`	`XmlWinEventLog`
Integration	✅ Passing	Dataset	`XmlWinEventLog:Microsoft-Windows-Sysmon/Operational`	`XmlWinEventLog`

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub | Version: 1