Name:Windows Modify Registry on Smart Card Group Policy id:1522145a-8e86-4f83-89a8-baf62a8f489d version:2 date:2024-09-30 author:Teoderick Contreras, Splunk status:production type:Anomaly Description:This analytic is developed to detect suspicious registry modifications targeting the "scforceoption" key. Altering this key enforces smart card login for all users, potentially disrupting normal access methods. Unauthorized changes to this setting could indicate an attempt to restrict access or force a specific authentication method, possibly signifying malicious intent to manipulate system security protocols. 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\\CurrentVersion\\Policies\\System\\scforceoption*" Registry.registry_value_data="0x00000001" 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_modify_registry_on_smart_card_group_policy_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 `Processes` node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product. known_false_positives:administrators may enable or disable this feature that may cause some false positive. References: -https://www.bleepingcomputer.com/news/security/new-shrinklocker-ransomware-uses-bitlocker-to-encrypt-your-files/ 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: - 'ShrinkLocker' asset_type:Endpoint confidence:50 impact:50 message:A registry modification in Windows Smart Card Group Policy registry settings on $dest$ mitre_attack_id: - 'T1112' observable: name:'dest' type:'Endpoint' - role: - 'Victim' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - '_time' - 'Registry.registry_path' - 'Registry.registry_key_name' - 'Registry.registry_value_name' - 'Registry.registry_key_name' - 'Registry.user' - 'Registry.dest' - 'Registry.action' - 'Registry.registry_value_data' - 'Registry.process_guid' risk_score:25 security_domain:endpoint
