Name:Monitor Registry Keys for Print Monitors id:f5f6af30-7ba7-4295-bfe9-07de87c01bbc version:9 date:2024-12-08 author:Teoderick Contreras, Splunk, Steven Dick, Bhavin Patel status:production type:TTP Description:The following analytic detects modifications to the registry key `HKLM\SYSTEM\CurrentControlSet\Control\Print\Monitors`. It leverages data from the Endpoint.Registry data model, focusing on events where the registry path is modified. This activity is significant because attackers can exploit this registry key to load arbitrary .dll files, which will execute with elevated SYSTEM permissions and persist after a reboot. If confirmed malicious, this could allow attackers to maintain persistence, execute code with high privileges, and potentially compromise the entire system. 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.action=modified AND Registry.registry_path="*CurrentControlSet\\Control\\Print\\Monitors*") 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)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `monitor_registry_keys_for_print_monitors_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:You will encounter noise from legitimate print-monitor registry entries. References: 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: - 'Suspicious Windows Registry Activities' - 'Windows Persistence Techniques' - 'Windows Registry Abuse' asset_type:Endpoint confidence:80 impact:80 message:New print monitor added on $dest$ mitre_attack_id: - 'T1547.010' - 'T1547' observable: name:'dest' type:'Endpoint' - role: - 'Victim' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - '_time' - '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
