Name:Windows Modify Registry AuthenticationLevelOverride id:6410a403-36bb-490f-a06a-11c3be7d2a41 version:3 date:2024-09-30 author:Teoderick Contreras, Splunk status:production type:Anomaly Description:The following analytic detects modifications to the Windows registry key "AuthenticationLevelOverride" within the Terminal Server Client settings. It leverages data from the Endpoint.Registry datamodel to identify changes where the registry value is set to 0x00000000. This activity is significant as it may indicate an attempt to override authentication levels for remote connections, a tactic used by DarkGate malware for malicious installations. If confirmed malicious, this could allow attackers to gain unauthorized remote access, potentially leading to data exfiltration or further 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 = "*\\Terminal Server Client\\AuthenticationLevelOverride" Registry.registry_value_data = 0x00000000 by Registry.registry_path Registry.registry_value_name Registry.registry_value_data Registry.process_guid Registry.action Registry.user Registry.dest | `drop_dm_object_name(Registry)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_modify_registry_authenticationleveloverride_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. Also make sure that this registry was included in your config files ex. sysmon config to be monitored. known_false_positives:Administrators may enable or disable this feature that may cause some false positive, however is not common. Filter as needed. References: -https://malpedia.caad.fkie.fraunhofer.de/details/win.darkgate 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: - 'DarkGate Malware' asset_type:Endpoint confidence:70 impact:70 message:the registry for authentication level settings was modified on $dest$. mitre_attack_id: - 'T1112' 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_path' - 'Registry.user' - 'Registry.dest' - 'Registry.registry_value_name' - 'Registry.action' security_domain:endpoint
