Name:Windows Remote Services Allow Remote Assistance id:9bce3a97-bc97-4e89-a1aa-ead151c82fbb version:3 date:2024-09-30 author:Teoderick Contreras, Splunk status:production type:Anomaly Description:The following analytic detects modifications in the Windows registry to enable remote desktop assistance on a targeted machine. It leverages data from the Endpoint.Registry datamodel, specifically monitoring changes to the "Control\\Terminal Server\\fAllowToGetHelp" registry path. This activity is significant because enabling remote assistance via registry is uncommon and often associated with adversaries or malware like Azorult. If confirmed malicious, this could allow an attacker to remotely access and control the compromised host, leading to potential 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= "*\\Control\\Terminal Server\\fAllowToGetHelp*" 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_remote_services_allow_remote_assistance_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. References: -https://docs.microsoft.com/en-us/windows-hardware/customize/desktop/unattend/microsoft-windows-remoteassistance-exe-fallowtogethelp -https://app.any.run/tasks/a6f2ffe2-e6e2-4396-ae2e-04ea0143f2d8/ 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: - 'Azorult' asset_type:Endpoint confidence:70 impact:70 message:the registry for rdp protocol was modified to enable in $dest$ mitre_attack_id: - 'T1021.001' - 'T1021' observable: name:'dest' type:'Endpoint' - role: - 'Victim' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - '_time' - 'Registry.registry_key_name' - 'Registry.registry_path' - 'Registry.user' - 'Registry.dest' - 'Registry.registry_value_name' - 'Registry.action' risk_score:49 security_domain:endpoint
