splunk-security_content/docs/_posts/2021-10-18-disable_schedule_task.md

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title	excerpt	categories	last_modified_at	toc	toc_label	tags
Disable Schedule Task	Disable or Modify Tools, Impair Defenses	Endpoint	2021-10-18	true		Disable or Modify Tools Defense Evasion Impair Defenses Defense Evasion Splunk Enterprise Splunk Enterprise Security Splunk Cloud Endpoint

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Description

This analytic is to detect a suspicious commandline to disable existing schedule task. This technique is used by adversaries or commodity malware like IceID to disable security application (AV products) in the targetted host to evade detections. This TTP is a good pivot to check further why and what other process run before and after this detection. check which process execute the commandline and what task is disabled. parent child process is quite valuable in this scenario too.

• Type: TTP
• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
• Datamodel: Endpoint
• Last Updated: 2021-10-18
• Author: Teoderick Contreras, Splunk
• ID: db596056-3019-11ec-a9ff-acde48001122

ATT&CK

ID	Technique	Tactic
T1562.001	Disable or Modify Tools	Defense Evasion

| T1562 | Impair Defenses | Defense Evasion |

Search

| tstats `security_content_summariesonly` count  min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name=schtasks.exe Processes.process=*/change*  Processes.process=*/disable* by Processes.user Processes.process_name Processes.process Processes.parent_process_name Processes.parent_process Processes.dest 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `disable_schedule_task_filter`

Associated Analytic Story

• IcedID

How To Implement

To successfully implement this search, you need to be ingesting logs with the process name, parent process, and command-line executions from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.

Required field

• _time
• Processes.user
• Processes.process_name
• Processes.parent_process_name
• Processes.dest

Kill Chain Phase

• Exploitation

Known False Positives

admin may disable problematic schedule task

RBA

Risk Score	Impact	Confidence	Message
56.0	70	80	schtask process with commandline process to disable schedule task in dest

Reference

• https://thedfirreport.com/2021/10/18/icedid-to-xinglocker-ransomware-in-24-hours/

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/malware/icedid/disable_schtask/sysmon.log

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