WS FTP Remote Code Execution

name: WS FTP Remote Code Execution
id: b84e8f39-4e7b-4d4f-9e7c-fcd29a227845
version: 11
creation_date: '2023-10-01'
modification_date: '2026-05-13'
author: Michael Haag, Splunk
status: production
type: TTP
description: |-
    The following analytic detects potential Remote Code Execution (RCE) attempts exploiting CVE-2023-40044 in WS_FTP software.
    It identifies HTTP POST requests to the "/AHT/AhtApiService.asmx/AuthUser" URL with a status code of 200.
    This detection leverages the Web datamodel to monitor specific URL patterns and HTTP status codes. This activity is significant as it may indicate an exploitation attempt, potentially allowing an attacker to execute arbitrary code on the server.
    If confirmed malicious, this could lead to unauthorized access, data exfiltration, or further compromise of the affected system.
data_source:
    - Suricata
search: |-
    | tstats `security_content_summariesonly`
      count min(_time) as firstTime
            max(_time) as lastTime
    
    FROM datamodel=Web WHERE
    
    Web.url="*/AHT/AhtApiService.asmx/AuthUser"
    Web.status=200
    Web.http_method="POST"
    
    BY Web.http_user_agent Web.status Web.http_method
       Web.url Web.url_length Web.src Web.dest
    
    | `drop_dm_object_name("Web")`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `ws_ftp_remote_code_execution_filter`
how_to_implement: |-
    The following analytic requires the Web datamodel. Ensure data source is mapped correctly or modify and tune for your data source.
known_false_positives: |-
    If WS_FTP Server is not in use, this analytic will not return results. Monitor and tune for your environment.
    Note the MetaSploit module is focused on only hitting /AHT/ and not the full /AHT/AhtApiService.asmx/AuthUser URL.
references:
    - https://github.com/projectdiscovery/nuclei-templates/pull/8296/files
    - https://www.assetnote.io/resources/research/rce-in-progress-ws-ftp-ad-hoc-via-iis-http-modules-cve-2023-40044
    - https://github.com/rapid7/metasploit-framework/pull/18414
finding:
    title: Potential WS FTP Remote Code Execution detected against URL $url$ on $dest$ from $src$
    entity:
        field: dest
        type: system
        score: 50
threat_objects:
    - field: src
      type: ip_address
analytic_story:
    - WS FTP Server Critical Vulnerabilities
asset_type: Web Server
cve:
    - CVE-2023-40044
mitre_attack_id:
    - T1190
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: web
security_domain: network