Detection: Windows Disable or Modify Tools Via Taskkill

Description

The following analytic identifies the use of taskkill.exe to forcibly terminate processes. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on command-line executions that include specific taskkill parameters. This activity is significant because it can indicate attempts to disable security tools or disrupt legitimate applications, a common tactic in malware operations. If confirmed malicious, this behavior could allow attackers to evade detection, disrupt system stability, and potentially gain further control over the compromised system.

Search

1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name = "taskkill.exe" Processes.process IN ("* /f*", "* /t*") Processes.process IN ("* /im*", "* /pid*") by Processes.parent_process_name Processes.parent_process Processes.process_name Processes.process Processes.process_id Processes.process_guid  Processes.user Processes.dest 
3| `drop_dm_object_name("Processes")` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `windows_disable_or_modify_tools_via_taskkill_filter`

Data Source

Name	Platform	Sourcetype	Source
CrowdStrike ProcessRollup2	N/A	'crowdstrike:events:sensor'	'crowdstrike'
Sysmon EventID 1	Windows	'xmlwineventlog'	'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'
Windows Event Log Security 4688	Windows	'xmlwineventlog'	'XmlWinEventLog:Security'

Macros Used

Annotations

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Implementation

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

Network administrator can use this application to kill process during audit or investigation.

Associated Analytic Story

• NjRAT

Risk Based Analytics (RBA)

References

• https://malpedia.caad.fkie.fraunhofer.de/details/win.njrat

Detection Testing

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

Source: GitHub | Version: 4