Name:Windows Scheduled Task DLL Module Loaded id:bc5b2304-f241-419b-874a-e927f667b7b6 version:3 date:2024-09-30 author:Teoderick Contreras, Splunk status:production type:TTP Description:The following analytic detects instances where the taskschd.dll is loaded by processes running in suspicious or writable directories. This activity is unusual, as legitimate processes that load taskschd.dll typically reside in protected system locations. Malware or threat actors may attempt to load this DLL from writable or non-standard directories to manipulate the Task Scheduler and execute malicious tasks. By identifying processes that load taskschd.dll in these unsafe locations, this detection helps security analysts flag potentially malicious activity and investigate further to prevent unauthorized system modifications. Data_source:
how_to_implement:To successfully implement this search, you need to be ingesting logs with the process name and imageloaded executions from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA. known_false_positives:Third party Legitimate application may load this task schedule dll module. References: -https://www.proofpoint.com/us/blog/threat-insight/chinese-malware-appears-earnest-across-cybercrime-threat-landscape -https://www.fortinet.com/blog/threat-research/valleyrat-campaign-targeting-chinese-speakers 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: - 'ValleyRAT' asset_type:Endpoint confidence:80 impact:80 message:A taskschd.dll was loaded by a process - [$Image$] on [$dest$] mitre_attack_id: - 'T1053' observable: name:'dest' type:'Hostname' - role: - 'Victim' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - '_time' - 'Image' - 'ImageLoaded' - 'process_name' - 'dest' - 'EventCode' - 'Signed' - 'ProcessId' risk_score:64 security_domain:endpoint
