Windows Shell Process from CrushFTP

name: Windows Shell Process from CrushFTP
id: 459628e3-1b00-4e9b-9e5b-7da8961aea35
version: 7
creation_date: '2025-04-14'
modification_date: '2026-05-13'
author: Michael Haag, Splunk
status: production
type: TTP
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.
data_source:
    - Sysmon EventID 1
    - Windows Event Log Security 4688
    - CrowdStrike ProcessRollup2
search: |-
    | 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
    | `drop_dm_object_name(Processes)`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `windows_shell_process_from_crushftp_filter`
how_to_implement: 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: No false positives have been identified at this time.
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2025-31161
    - https://www.crushftp.com/crush11wiki/Wiki.jsp?page=Update
    - https://www.huntress.com/blog/crushftp-cve-2025-31161-auth-bypass-and-post-exploitation
finding:
    title: Possible CrushFTP exploitation detected on $dest$ related to CVE-2025-31161.
    entity:
        field: dest
        type: system
        score: 50
analytic_story:
    - CrushFTP Vulnerabilities
asset_type: Endpoint
cve:
    - CVE-2025-31161
mitre_attack_id:
    - T1059.001
    - T1059.003
    - T1190
    - T1505
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint