Short Lived Scheduled Task

Try in Splunk Security Cloud

Description

The following analytic leverages Windows Security EventCode 4698, A scheduled task was created and Windows Security EventCode 4699, A scheduled task was deleted to identify scheduled tasks created and deleted in less than 30 seconds. This behavior may represent a lateral movement attack abusing the Task Scheduler to obtain code execution. Red Teams and adversaries alike may abuse the Task Scheduler for lateral movement and remote code execution.

• Type: TTP

• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

• Last Updated: 2021-12-03
• Author: Mauricio Velazco, Splunk
• ID: 6fa31414-546e-11ec-adfa-acde48001122

Annotations

ATT&CK

ATT&CK

ID	Technique	Tactic
T1053.005	Scheduled Task	Execution, Persistence, Privilege Escalation

Kill Chain Phase

• Exploitation

NIST

CIS20

CVE

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 
| table _time, ComputerName, Account_Name, Command, Task_Name, short_lived 
| `short_lived_scheduled_task_filter` 

Macros

The SPL above uses the following Macros:

• wineventlog_security

short_lived_scheduled_task_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

• _time
• dest
• ComputerName
• Account_Name
• Task_Name
• Description
• Command

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.

Associated Analytic Story

• Active Directory Lateral Movement
• CISA AA22-257A

RBA

Risk Score	Impact	Confidence	Message
81.0	90	90	A windows scheduled task was created and deleted in 30 seconds on $ComputerName$

The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

• https://attack.mitre.org/techniques/T1053/005/
• https://docs.microsoft.com/en-us/windows/win32/taskschd/about-the-task-scheduler

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

• https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1053.005/lateral_movement/windows-security.log

source | version: 1