Detection rules › Splunk

Windows Scheduled Task Created in a Group Policy Object

Status
production
Severity
medium
Group by
access_mask, computer_name, relative_target_name, share_name
Author
Raven Tait, Splunk
Source
github.com/splunk/security_content

When a scheduled task is created within a Group Policy, a characteristic file ScheduledTasks.xml with its definition is created in the respective subfolder of the SYSVOL share. This rule can hit on legitimate GPO scheduled task creation, but this does not happen often and is therefore an effective way to monitor for malicious scheduled tasks.

MITRE ATT&CK coverage

Event coverage

Rule body splunk

name: Windows Scheduled Task Created in a Group Policy Object
id: 350032cd-3d3f-4278-afc8-e01cf5c33524
version: 2
creation_date: '2026-05-05'
modification_date: '2026-05-13'
author: Raven Tait, Splunk
status: production
type: TTP
description: |-
    When a scheduled task is created within a Group Policy, a characteristic file ScheduledTasks.xml with its definition is created in the respective subfolder of the SYSVOL share.
    This rule can hit on legitimate GPO scheduled task creation, but this does not happen often and is therefore an effective way to monitor for malicious scheduled tasks.
data_source:
    - Windows Event Log Security 5145
search: |-
    `wineventlog_security`
    EventID=5145
    ShareName="\\*\\SYSVOL"
    RelativeTargetName="*\\ScheduledTasks\\ScheduledTasks.xml"
    RelativeTargetName="*\\Policies\\*"
    AccessList IN (
        "*%%4417*",
        "*%%4418*"
    )
    | fillnull
    | stats count min(_time) as firstTime
                  max(_time) as lastTime
      by Computer ShareName RelativeTargetName AccessList
    
    | rename Computer as dest
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `windows_scheduled_task_created_in_a_group_policy_object_filter`
how_to_implement: The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint` data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
known_false_positives: Some legitimate scheduled tasks are occasionally created via Group Policy Objects in managed environments. Filter alerts for approved GPO deployments to reduce false positives.
references:
    - https://docs.microsoft.com/en-us/windows/security/threat-protection/auditing/event-5145
drilldown_searches:
    - earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
      name: View the detection results for - "$user$" and "$dest$"
      search: '%original_detection_search% | search  user = "$user$" dest = "$dest$"'
    - name: View risk events for the last 7 days for - "$user$" and "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$", "$dest$") | 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"
finding:
    title: Potential Scheduled task created in a Group Policy Object activity observed on $dest$.
    entity:
        field: dest
        type: system
        score: 50
analytic_story:
    - Scheduled Tasks
    - Windows Persistence Techniques
    - Living Off The Land
asset_type: Endpoint
mitre_attack_id:
    - T1484.001
    - T1053.005
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1484.001/snapattack/snapattack.log
          source: XmlWinEventLog:Security
          sourcetype: XmlWinEventLog
      test_type: unit

Stages and Predicates

Stage 1: search

`wineventlog_security`
EventID=5145
ShareName="\\*\\SYSVOL"
RelativeTargetName="*\\ScheduledTasks\\ScheduledTasks.xml"
RelativeTargetName="*\\Policies\\*"
AccessList IN (
    "*%%4417*",
    "*%%4418*"
)

Stage 2: fillnull

| fillnull

Stage 3: stats

| stats count min(_time) as firstTime
              max(_time) as lastTime
  by Computer ShareName RelativeTargetName AccessList

Stage 4: rename

| rename Computer as dest

Stage 5: search

| `security_content_ctime(firstTime)`

Stage 6: search

| `security_content_ctime(lastTime)`

Stage 7: search

| `windows_scheduled_task_created_in_a_group_policy_object_filter`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
AccessListin
  • "*%%4417*" corpus 11 (sigma 8, elastic 2, splunk 1)
  • "*%%4418*" corpus 3 (sigma 1, splunk 1, kusto 1)
EventIDeq
  • 5145 corpus 18 (splunk 16, kusto 2)
RelativeTargetNameeq
  • "*\\Policies\\*"
  • "*\\ScheduledTasks\\ScheduledTasks.xml"
ShareNameeq
  • "\\*\\SYSVOL"