Name:Short Lived Scheduled Task id:6fa31414-546e-11ec-adfa-acde48001122 version:12 date:None author:Mauricio Velazco, Splunk status:production type:Anomaly Description:The following analytic detects the creation and deletion of scheduled tasks within a short time frame (less than 30 seconds) using Windows Security EventCodes 4698 and 4699.
This behavior is identified by analyzing Windows Security Event Logs and leveraging the Windows TA for parsing.
Such activity may indicate lateral movement or remote code execution attempts by adversaries.
If confirmed malicious, this could lead to unauthorized access, data exfiltration, or execution of malicious payloads, necessitating prompt investigation and response by security analysts. Data_source:
-Windows Event Log Security 4698
-Windows Event Log Security 4699
search:`wineventlog_security` EventCode IN (4698, 4699) | xmlkv object_attrs | transaction TaskName dest startswith=(EventCode=4698) endswith=(EventCode=4699) maxspan=30s | stats count min(_time) AS firstTime max(_time) AS lastTime by Command TaskName user dest RunLevel | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `short_lived_scheduled_task_filter`
how_to_implement:To successfully implement this search, you need to be ingesting Windows Security Event Logs with 4698 EventCode enabled. The Windows TA is also required. known_false_positives:Although uncommon, legitimate applications may create and delete a Scheduled Task within 30 seconds. Filter as needed. References: -https://attack.mitre.org/techniques/T1053/005/ -https://docs.microsoft.com/en-us/windows/win32/taskschd/about-the-task-scheduler 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 ("$dest$") | 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:'7d' latest_offset:'0' analytic_story:['Active Directory Lateral Movement', 'CISA AA22-257A', 'CISA AA23-347A', 'Compromised Windows Host', 'Scheduled Tasks']
