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Description

The following analytic utilizes Windows Security EventCode 4698, "A scheduled task was created," and EventCode 4699, "A scheduled task was deleted," to identify scheduled tasks that are created and deleted within a short time frame of less than 30 seconds. This behavior is indicative of a potential lateral movement attack where the Task Scheduler is abused to achieve code execution. Both red teams and adversaries may exploit the Task Scheduler for lateral movement and remote code execution.
To implement this analytic, ensure that you are ingesting Windows Security Event Logs with EventCode 4698 enabled. Additionally, the Windows TA (Technology Add-on) is required to parse and extract the necessary information from the logs.
It's important to note that while uncommon, legitimate applications may create and delete scheduled tasks within a short duration. Analysts should filter the results based on the specific context and environment to reduce false positives.
Identifying short-lived scheduled tasks is valuable for a SOC as it can indicate malicious activities attempting to move laterally or execute unauthorized code on Windows systems. By detecting and investigating these events, security analysts can respond promptly to prevent further compromise and mitigate potential risks. The impact of a true positive could range from unauthorized access to data exfiltration or the execution of malicious payloads.

  • 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
  • Installation
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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 `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`

Macros

The SPL above uses the following Macros:

:information_source: 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

RBA

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

:information_source: 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

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

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