Name:Windows Impair Defense Disable PUA Protection id:fbfef407-cfee-4866-88c1-f8de1c16147c version:3 date:2024-09-30 author:Teoderick Contreras, Splunk status:production type:TTP Description:The following analytic detects a modification in the Windows registry to disable Windows Defender PUA protection by setting PUAProtection to 0. This detection leverages data from the Endpoint.Registry datamodel, focusing on registry path changes related to Windows Defender. Disabling PUA protection is significant as it reduces defenses against Potentially Unwanted Applications (PUAs), which, while not always malicious, can negatively impact user experience and security. If confirmed malicious, this activity could allow an attacker to introduce adware, browser toolbars, or other unwanted software, potentially compromising system integrity and user productivity. Data_source:
-Sysmon EventID 12
-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\\PUAProtection" Registry.registry_value_data="0x00000000" by Registry.registry_key_name Registry.user Registry.registry_path Registry.registry_value_data Registry.action Registry.dest | `drop_dm_object_name(Registry)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_impair_defense_disable_pua_protection_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 ("$dest$") starthoursago=168 | 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:'$info_min_time$' latest_offset:'$info_max_time$' tags: analytic_story: - 'Windows Defense Evasion Tactics' - 'Windows Registry Abuse' asset_type:Endpoint confidence:70 impact:70 message:Windows Defender PUA protection set to disable on $dest$. mitre_attack_id: - 'T1562.001' - 'T1562' observable: name:'dest' type:'Endpoint' - role: - 'Victim' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' risk_score:49 required_fields: - '_time' - 'Registry.registry_key_name' - 'Registry.registry_value_name' - 'Registry.dest' - 'Registry.user' - 'Registry.registry_path' - 'Registry.action' security_domain:endpoint
