Name:Windows Defender Exclusion Registry Entry id:13395a44-4dd9-11ec-9df7-acde48001122 version:8 date:2024-12-08 author:Teoderick Contreras, Splunk, Steven Dick status:production type:TTP Description:The following analytic detects modifications to the Windows Defender exclusion registry entries. It leverages endpoint registry data to identify changes in the registry path "*\\SOFTWARE\\Policies\\Microsoft\\Windows Defender\\Exclusions\\*". This activity is significant because adversaries often modify these entries to bypass Windows Defender, allowing malicious code to execute without detection. If confirmed malicious, this behavior could enable attackers to evade antivirus defenses, maintain persistence, and execute further malicious activities undetected. 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 = "*\\SOFTWARE\\Policies\\Microsoft\\Windows Defender\\Exclusions\\*") BY Registry.dest Registry.user Registry.registry_path Registry.registry_key_name Registry.registry_value_name Registry.registry_value_data Registry.process_guid | `drop_dm_object_name(Registry)` | where isnotnull(registry_value_data) | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_defender_exclusion_registry_entry_filter`
how_to_implement:To successfully implement this search, you need to be ingesting logs with the registry value name, registry path, and registry value data from your endpoints. If you are using Sysmon, you must have at least version 2.0 of the official Sysmon TA. https://splunkbase.splunk.com/app/5709 known_false_positives:admin or user may choose to use this windows features. References: -https://tccontre.blogspot.com/2020/01/remcos-rat-evading-windows-defender-av.html -https://app.any.run/tasks/cf1245de-06a7-4366-8209-8e3006f2bfe5/ -https://www.microsoft.com/security/blog/2022/01/15/destructive-malware-targeting-ukrainian-organizations/ drilldown_searches: name:'View the detection results for - "$user$" and "$dest$"' search:'%original_detection_search% | search user = "$user$" dest = "$dest$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$user$" and "$dest$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$", "$dest$") 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: - 'Remcos' - 'Windows Defense Evasion Tactics' - 'Azorult' - 'Qakbot' - 'Warzone RAT' - 'ValleyRAT' asset_type:Endpoint confidence:80 impact:80 message:Exclusion registry $registry_path$ modified or added on $dest$ for Windows Defender mitre_attack_id: - 'T1562.001' - 'T1562' observable: name:'user' type:'User' - role: - 'Victim' name:'dest' type:'Hostname' - role: - 'Victim' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - 'Registry.dest' - 'Registry.registry_value_name' - 'Registry.registry_key_name' - 'Registry.registry_path' - 'Registry.registry_value_data' - 'Registry.process_guid' risk_score:64 security_domain:endpoint
