Windows File Transfer Protocol In Non-Common Process Path

name: Windows File Transfer Protocol In Non-Common Process Path
id: 0f43758f-1fe9-470a-a9e4-780acc4d5407
version: 9
date: '2026-03-10'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: The following analytic detects FTP connections initiated by processes located in non-standard installation paths on Windows systems. It leverages Sysmon EventCode 3 to identify network connections where the process image path does not match common directories like "Program Files" or "Windows\System32". This activity is significant as FTP is often used by adversaries and malware, such as AgentTesla, for Command and Control (C2) communications to exfiltrate stolen data. If confirmed malicious, this could lead to unauthorized data transfer, exposing sensitive information and compromising the integrity of the affected host.
data_source:
    - Sysmon EventID 3
search: |
    `sysmon`
    EventCode=3
    NOT Image IN(
      "C:\\Program Files \(x86\)\\*",
      "C:\\Program Files\\*",
      "C:\\Windows\\System32\\*",
      "C:\\Windows\\SysWOW64\\*"
    )
    (
      DestinationPortName="ftp"
      OR
      DestinationPort=21
    )
    | stats count min(_time) as firstTime
            max(_time) as lastTime

    by action app dest dest_ip dest_port direction dvc protocol protocol_version
       src src_ip src_port transport user vendor_product process_name
       process_exec process_guid process_id
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `windows_file_transfer_protocol_in_non_common_process_path_filter`
how_to_implement: To successfully implement this search, you need to be ingesting logs with the process name and sysmon eventcode = 3 connection events from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.
known_false_positives: Third party FTP based applications will trigger this. Apply additional filters as needed. Also consider excluding known FTP based clients installed outside of the Program Files and Windows directories.
references:
    - https://malpedia.caad.fkie.fraunhofer.de/details/win.agent_tesla
drilldown_searches:
    - name: View the detection results for - "$dest$"
      search: '%original_detection_search% | search  dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") starthoursago=168  | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
rba:
    message: a process $process_name$ is having a FTP connection to $dest$ in $dest_ip$
    risk_objects:
        - field: dest
          type: system
          score: 20
    threat_objects: []
tags:
    analytic_story:
        - AgentTesla
        - Snake Keylogger
        - Hellcat Ransomware
    asset_type: Endpoint
    mitre_attack_id:
        - T1071.003
    product:
        - Splunk Enterprise
        - Splunk Enterprise Security
        - Splunk Cloud
    security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/malware/agent_tesla/agent_tesla_ftp/sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog