Detection rules › Splunk
Windows Impair Defense Change Win Defender Throttle Rate
The following analytic detects modifications to the ThrottleDetectionEventsRate registry setting in Windows Defender. It leverages data from the Endpoint.Registry datamodel to identify changes in the registry path related to Windows Defender's event logging rate. This activity is significant because altering the ThrottleDetectionEventsRate can reduce the frequency of logged detection events, potentially masking malicious activities. If confirmed malicious, this could allow an attacker to evade detection by decreasing the visibility of security events, thereby hindering incident response and forensic investigations.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Defense Impairment | T1685 Disable or Modify Tools |
Event coverage
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 13 | RegistryEvent (Value Set) |
Rule body splunk
name: Windows Impair Defense Change Win Defender Throttle Rate
id: f7da5fca-9261-43de-a4d0-130dad1e4f4d
version: 11
creation_date: '2024-01-30'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: TTP
description: The following analytic detects modifications to the ThrottleDetectionEventsRate registry setting in Windows Defender. It leverages data from the Endpoint.Registry datamodel to identify changes in the registry path related to Windows Defender's event logging rate. This activity is significant because altering the ThrottleDetectionEventsRate can reduce the frequency of logged detection events, potentially masking malicious activities. If confirmed malicious, this could allow an attacker to evade detection by decreasing the visibility of security events, thereby hindering incident response and forensic investigations.
data_source:
- Sysmon EventID 13
search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Registry where Registry.registry_path= "*\\Windows Defender\\NIS\\Consumers\\IPS\\ThrottleDetectionEventsRate" by Registry.action Registry.dest Registry.process_guid Registry.process_id Registry.registry_hive Registry.registry_path Registry.registry_key_name Registry.registry_value_data Registry.registry_value_name Registry.registry_value_type Registry.status Registry.user Registry.vendor_product | `drop_dm_object_name(Registry)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_impair_defense_change_win_defender_throttle_rate_filter`'
how_to_implement: To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the `Endpoint` datamodel in the `Registry` node.
known_false_positives: It is unusual to turn this feature off a Windows system since it is a default security control, although it is not rare for some policies to disable it. Although no false positives have been identified, use the provided filter macro to tune the search.
references:
- https://x.com/malmoeb/status/1742604217989415386?s=20
- https://github.com/undergroundwires/privacy.sexy
drilldown_searches:
- name: View the detection results for - "$dest$"
search: '%original_detection_search% | search dest = "$dest$"'
earliest_offset: $info_min_time$
latest_offset: $info_max_time$
- name: View risk events for the last 7 days for - "$dest$"
search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
earliest_offset: 7d
latest_offset: "0"
finding:
title: Windows Defender ThrottleDetectionEventsRate feature was modified on $dest$.
entity:
field: dest
type: system
score: 50
analytic_story:
- Windows Defense Evasion Tactics
- Windows Registry Abuse
asset_type: Endpoint
mitre_attack_id:
- T1685
product:
- Splunk Enterprise
- Splunk Enterprise Security
- Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
- name: True Positive Test
attack_data:
- data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1562.001/disable-windows-security-defender-features/windefender-bypas-2-sysmon.log
source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
sourcetype: XmlWinEventLog
test_type: unit
Stages and Predicates
Stage 1: tstats
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Registry where Registry.registry_path= "*\\Windows Defender\\NIS\\Consumers\\IPS\\ThrottleDetectionEventsRate" by Registry.action Registry.dest Registry.process_guid Registry.process_id Registry.registry_hive Registry.registry_path Registry.registry_key_name Registry.registry_value_data Registry.registry_value_name Registry.registry_value_type Registry.status Registry.user Registry.vendor_product
Stage 2: search
| `drop_dm_object_name(Registry)`
Stage 3: search
| `security_content_ctime(firstTime)`
Stage 4: search
| `security_content_ctime(lastTime)`
Stage 5: search
| `windows_impair_defense_change_win_defender_throttle_rate_filter`
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.
| Field | Kind | Values |
|---|---|---|
Registry.registry_path | eq |
|