Detection: Windows User Profile Binary Terminating Process Via Taskkill

Description

The following analytic detects taskkill.exe being launched with a process ID (/pid) argument by an executable that resides directly within a user profile folder, such as the Downloads or Desktop folder. Filtering for parent processes located two to three directory levels deep under root folder. This activity is significant because browser hijackers and adware droppers executed from the Downloads folder forcefully terminate the running browser by PID so that they can modify its profile and relaunch it with their own settings. If confirmed malicious, this could allow an attacker to tamper with browser preference files, side-load extensions and redirect the victim's browsing traffic.

Search

 1
 2| tstats `security_content_summariesonly`
 3  count min(_time) as firstTime
 4        max(_time) as lastTime
 5
 6from datamodel=Endpoint.Processes where
 7
 8(
 9    Processes.process_name=taskkill.exe
10    OR
11    Processes.original_file_name=taskkill.exe
12)
13Processes.process IN ("* /pid *", "* -pid *")
14Processes.parent_process_path="*:\\Users\\*"
15
16by Processes.action Processes.dest Processes.original_file_name Processes.parent_process
17   Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id
18   Processes.parent_process_name Processes.parent_process_path Processes.process Processes.process_exec
19   Processes.process_guid Processes.process_hash Processes.process_id Processes.process_integrity_level
20   Processes.process_name Processes.process_path Processes.user Processes.user_id Processes.vendor_product
21
22
23| `drop_dm_object_name(Processes)`
24
25| regex parent_process_path="(?i)^\\w+\\:\\\\(?:[^\\\\\\/\\x27\\x22]+\\\\){2,3}[^\\\\\\/\\x27\\x22]+\\.exe$"
26
27| `security_content_ctime(firstTime)`
28
29| `security_content_ctime(lastTime)`
30
31| `windows_user_profile_binary_terminating_process_via_taskkill_filter`

Data Source

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

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

Portable applications, installers and updaters executed from a user's Downloads or Desktop folder may legitimately use taskkill.exe to close a running instance of themselves or another application. Filter as needed based on the parent process name or path.

Associated Analytic Story

• Living Off The Land

• Browser Hijacking

Finding

Threat Objects

References

• https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/taskkill

• https://www.gdatasoftware.com/blog/2025/11/38298-learning-about-browser-hijacking

• https://www.joesandbox.com/analysis/1965188/0/html

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: 1