Detection rules › Splunk

Windows Impair Defenses Disable Win Defender Auto Logging

Status
production
Severity
low
Group by
TargetObject, computer_name, details, event_type, process_guid, process_id, registry_hive, registry_path, registry_status, registry_value_name, registry_value_type, user, vendor_product
Author
Teoderick Contreras, Splunk
Source
github.com/splunk/security_content

The following analytic detects the disabling of Windows Defender logging by identifying changes to the Registry keys DefenderApiLogger or DefenderAuditLogger set to disable. It leverages data from the Endpoint.Registry datamodel to monitor specific registry paths and values. This activity is significant as it is commonly associated with Remote Access Trojan (RAT) malware attempting to evade detection. If confirmed malicious, this action could allow an attacker to conceal their activities, making it harder to detect further malicious actions and maintain persistence on the compromised endpoint.

MITRE ATT&CK coverage

TacticTechniques
Defense ImpairmentT1685 Disable or Modify Tools

Event coverage

ProviderEventTitle
SysmonEvent ID 13RegistryEvent (Value Set)

Rule body splunk

name: Windows Impair Defenses Disable Win Defender Auto Logging
id: 76406a0f-f5e0-4167-8e1f-337fdc0f1b0c
version: 12
creation_date: '2020-11-06'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: The following analytic detects the disabling of Windows Defender logging by identifying changes to the Registry keys DefenderApiLogger or DefenderAuditLogger set to disable. It leverages data from the Endpoint.Registry datamodel to monitor specific registry paths and values. This activity is significant as it is commonly associated with Remote Access Trojan (RAT) malware attempting to evade detection. If confirmed malicious, this action could allow an attacker to conceal their activities, making it harder to detect further malicious actions and maintain persistence on the compromised endpoint.
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 = "*WMI\\Autologger\\DefenderApiLogger\\Start" OR Registry.registry_path = "*WMI\\Autologger\\DefenderAuditLogger\\Start")  Registry.registry_value_data ="0x00000000" 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_defenses_disable_win_defender_auto_logging_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://blog.malwarebytes.com/malwarebytes-news/2021/02/lazyscripter-from-empire-to-double-rat/
    - https://app.any.run/tasks/45f5d114-91ea-486c-ab01-41c4093d2861/
    - https://isc.sans.edu/diary/rss/28628
    - https://thedfirreport.com/2021/10/18/icedid-to-xinglocker-ransomware-in-24-hours/
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"
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 20
          message: Windows Defender Logger registry key set to 'disabled' on $dest$.
analytic_story:
    - Windows Defense Evasion Tactics
    - CISA AA23-347A
    - 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_defender_logging/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 = "*WMI\\Autologger\\DefenderApiLogger\\Start" OR Registry.registry_path = "*WMI\\Autologger\\DefenderAuditLogger\\Start")  Registry.registry_value_data ="0x00000000" 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_defenses_disable_win_defender_auto_logging_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.

FieldKindValues
Registry.registry_patheq
  • "*WMI\\Autologger\\DefenderApiLogger\\Start"
  • "*WMI\\Autologger\\DefenderAuditLogger\\Start"
Registry.registry_value_dataeq
  • "0x00000000" corpus 43 (splunk 35, elastic 8)