Detection: Windows Shell Process from CrushFTP

Updated Date: 2025-04-03 ID: 459628e3-1b00-4e9b-9e5b-7da8961aea35 Author: Michael Haag, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic identifies instances where CrushFTP's service process (crushftpservice.exe) spawns shell processes like cmd.exe or powershell.exe. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process creation events. This activity is significant because CrushFTP should not normally spawn interactive shell processes during regular operations. If confirmed malicious, this behavior could indicate successful exploitation of vulnerabilities like CVE-2025-31161, potentially allowing attackers to execute arbitrary commands with the privileges of the CrushFTP service.

Search

1
2| tstats `security_content_summariesonly` count values(Processes.process_name) as process_name values(Processes.process) as process min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.parent_process_name=crushftpservice.exe AND `process_cmd` OR `process_powershell` by Processes.dest Processes.parent_process Processes.original_file_name Processes.user Processes.action Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id Processes.parent_process_path Processes.process_exec Processes.process_guid Processes.process_hash Processes.process_id Processes.process_integrity_level Processes.process_path Processes.user_id Processes.vendor_product 
3| `drop_dm_object_name(Processes)` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)`
6| `windows_shell_process_from_crushftp_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

Name	Value
process_cmd	`(Processes.process_name=cmd.exe OR Processes.original_file_name=Cmd.Exe)`
windows_shell_process_from_crushftp_filter	`search *`

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

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1059.001	PowerShell	Execution
T1059.003	Windows Command Shell	Execution
T1190	Exploit Public-Facing Application	Initial Access
T1505	Server Software Component	Persistence

Delivery

Installation

DE.CM

CIS 10

Default Configuration

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

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Notable	Yes
Rule Title	`%name%`
Rule Description	`%description%`
Notable Event Fields	user, dest
Creates Risk Event	True

This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

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.

Known False Positives

Unknown. Filter as needed.

Associated Analytic Story

CrushFTP Vulnerabilities

Risk Based Analytics (RBA)

Risk Message:

Possible CrushFTP exploitation detected on $dest$ related to CVE-2025-31161.

Risk Object	Risk Object Type	Risk Score	Threat Objects
dest	system	65	No Threat Objects

References

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`XmlWinEventLog:Microsoft-Windows-Sysmon/Operational`	`XmlWinEventLog`
Integration	✅ Passing	Dataset	`XmlWinEventLog:Microsoft-Windows-Sysmon/Operational`	`XmlWinEventLog`

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