Name:Windows Impair Defense Set Win Defender Smart Screen Level To Warn id:cc2a3425-2703-47e7-818f-3dca1b0bc56f version:3 date:2024-09-30 author:Teoderick Contreras, Splunk status:production type:TTP Description:The following analytic detects modifications to the Windows registry that set the Windows Defender SmartScreen level to "warn." This detection leverages data from the Endpoint.Registry data model, specifically monitoring changes to the ShellSmartScreenLevel registry value. This activity is significant because altering SmartScreen settings to "warn" can reduce immediate suspicion from users, allowing potentially malicious executables to run with just a warning prompt. If confirmed malicious, this could enable attackers to execute harmful files, increasing the risk of successful malware deployment and subsequent system compromise. 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= "*\\Microsoft\\Windows\\System\\ShellSmartScreenLevel" Registry.registry_value_data="Warn" 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_set_win_defender_smart_screen_level_to_warn_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 SmartScreen Level to Warn 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
