Short Lived Scheduled Task

Name:Short Lived Scheduled Task
id:6fa31414-546e-11ec-adfa-acde48001122
version:5
date:2024-11-28
author:Mauricio Velazco, Splunk
status:production
type:TTP
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 is significant as it 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=4698 OR EventCode=4699
| xmlkv Message
| transaction Task_Name startswith=(EventCode=4698) endswith=(EventCode=4699)
| eval short_lived=case((duration<30),"TRUE")
| search short_lived = TRUE
| rename ComputerName as dest| table _time, dest, Account_Name, Command, Task_Name, short_lived
| `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 ("$dest$") 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:
    - 'Active Directory Lateral Movement'
    - 'CISA AA22-257A'
    - 'CISA AA23-347A'
    - 'Compromised Windows Host'
    - 'Scheduled Tasks'
  asset_type:Endpoint
  confidence:90
  impact:90
  message:A windows scheduled task was created and deleted in 30 seconds on $dest$
  mitre_attack_id:
    - 'T1053.005'
  observable:
    name:'dest'
    type:'Endpoint'
    - role:
      - 'Victim'
  product:
    - 'Splunk Enterprise'
    - 'Splunk Enterprise Security'
    - 'Splunk Cloud'
  required_fields:
    - '_time'
    - 'dest'
    - 'ComputerName'
    - 'Account_Name'
    - 'Task_Name'
    - 'Description'
    - 'Command'
  risk_score:81
  security_domain:endpoint

tests:
 name:'True Positive Test'
 attack_data:
  data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1053.005/lateral_movement/windows-security.log
  source: WinEventLog:Security
  sourcetype: WinEventLog
manual_test:None