Detection rules › Splunk

Windows Schtasks Create Run As System

Status
production
Severity
medium
Group by
IntegrityLevel, command_line, computer_name, event_action, original_file_name, parent_command_line, parent_process_guid, parent_process_id, parent_process_name, process_guid, process_hash, process_id, process_name, user, user_id, vendor_product
Author
Michael Haag, Splunk
Source
github.com/splunk/security_content

The following analytic detects the creation of a new scheduled task using Schtasks.exe to run as the SYSTEM user. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on command-line executions and process details. This activity is significant as it often indicates an attempt to gain elevated privileges or maintain persistence within the environment. If confirmed malicious, an attacker could execute code with SYSTEM-level privileges, potentially leading to data theft, ransomware deployment, or further system compromise. Immediate investigation and mitigation are crucial to prevent further damage.

Known false positives

  • False positives will be limited to legitimate applications creating a task to run as SYSTEM. Filter as needed based on parent process, or modify the query to have world writeable paths to restrict it.

MITRE ATT&CK coverage

Telemetry coverage

Rule body

name: Windows Schtasks Create Run As System
id: 41a0e58e-884c-11ec-9976-acde48001122
version: 14
creation_date: '2022-02-09'
modification_date: '2026-05-13'
author: Michael Haag, Splunk
status: production
type: TTP
description: The following analytic detects the creation of a new scheduled task using Schtasks.exe to run as the SYSTEM user. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on command-line executions and process details. This activity is significant as it often indicates an attempt to gain elevated privileges or maintain persistence within the environment. If confirmed malicious, an attacker could execute code with SYSTEM-level privileges, potentially leading to data theft, ransomware deployment, or further system compromise. Immediate investigation and mitigation are crucial to prevent further damage.
data_source:
    - Sysmon EventID 1
    - Windows Event Log Security 4688
    - CrowdStrike ProcessRollup2
search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where (Processes.process_name=schtasks.exe OR Processes.original_file_name=schtasks.exe) Processes.process="*/create *" Processes.process="*/ru *" Processes.process="*system*" by Processes.action Processes.dest Processes.original_file_name Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path Processes.process Processes.process_exec Processes.process_guid Processes.process_hash Processes.process_id Processes.process_integrity_level Processes.process_name Processes.process_path Processes.user Processes.user_id Processes.vendor_product | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_schtasks_create_run_as_system_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: False positives will be limited to legitimate applications creating a task to run as SYSTEM. Filter as needed based on parent process, or modify the query to have world writeable paths to restrict it.
references:
    - https://pentestlab.blog/2019/11/04/persistence-scheduled-tasks/
    - https://www.ired.team/offensive-security/persistence/t1053-schtask
    - https://thedfirreport.com/2022/02/07/qbot-likes-to-move-it-move-it/
finding:
    title: An $process_name$ was created on endpoint $dest$ attempting to spawn as SYSTEM.
    entity:
        field: dest
        type: system
        score: 50
threat_objects:
    - field: process_name
      type: process_name
analytic_story:
    - SolarWinds WHD RCE Post Exploitation
    - Medusa Ransomware
    - Windows Persistence Techniques
    - Qakbot
    - Scheduled Tasks
    - Castle RAT
asset_type: Endpoint
mitre_attack_id:
    - T1053.005
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint

Stages and Predicates

Stage 1: tstats

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where (Processes.process_name=schtasks.exe OR Processes.original_file_name=schtasks.exe) Processes.process="*/create *" Processes.process="*/ru *" Processes.process="*system*" by Processes.action Processes.dest Processes.original_file_name Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path Processes.process Processes.process_exec Processes.process_guid Processes.process_hash Processes.process_id Processes.process_integrity_level Processes.process_name Processes.process_path Processes.user Processes.user_id Processes.vendor_product

Stage 2: search

| `drop_dm_object_name(Processes)`

Stage 3: search

| `security_content_ctime(firstTime)`

Stage 4: search

| `security_content_ctime(lastTime)`

Stage 5: search

| `windows_schtasks_create_run_as_system_filter`

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
Processes.original_file_nameeq
  • "schtasks.exe" corpus 31 (sigma 18, elastic 9, splunk 4)
field:"OriginalFileName" kind:eq
Processes.processeq
  • "*/create *" corpus 5 (sigma 3, splunk 2)
  • "*/ru *" corpus 2 (sigma 1, splunk 1)
  • "*system*" corpus 9 (sigma 4, splunk 3, elastic 2)
field:"CommandLine" kind:eq
Processes.process_nameeq
  • "schtasks.exe" corpus 30 (elastic 19, splunk 11)
field:"process_name" kind:eq