Windows Unusual FileZilla XML Config Access

name: Windows Unusual FileZilla XML Config Access
id: 47dc0426-cbe4-4253-8b86-1a983c3f9951
version: 2
date: '2026-03-10'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: The following analytic identifies processes accessing FileZilla XML config files such as recentservers.xml and sitemanager.xml. It leverages Windows Security Event logs, specifically monitoring EventCode 4663, which tracks object access events. This activity is significant because it can indicate unauthorized access or manipulation of sensitive configuration files used by FileZilla, a popular FTP client. If confirmed malicious, this could lead to data exfiltration, credential theft, or further compromise of the system.
data_source:
    - Windows Event Log Security 4663
search: '`wineventlog_security` EventCode=4663  NOT (ProcessName IN("C:\\Program Files\\FileZilla FTP Client\\filezilla.exe", "C:\Program Files (x86)\\FileZilla FTP Client\\filezilla.exe", "C:\\Program Files\\Microsoft OneDrive\\OneDrive.exe", "C:\\Program Files (x86)\\Microsoft OneDrive\\OneDrive.exe")) file_path IN ("*FileZilla\\recentservers.xml*", "*FileZilla\\sitemanager.xml*") | stats count min(_time) as firstTime max(_time) as lastTime by  ObjectName ObjectType ProcessName AccessMask process_id EventCode Computer Caller_User_Name | rename Computer as dest Caller_User_Name as user ProcessName as process_name |  `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_unusual_filezilla_xml_config_access_filter`'
how_to_implement: To successfully implement this search, you must ingest Windows Security Event logs and track event code 4663. For 4663, enable "Audit Object Access" in Group Policy. Then check the two boxes listed for both "Success" and "Failure."
known_false_positives: a third party application can access the FileZilla XML config files. Filter is needed.
references:
    - https://www.trendmicro.com/en_us/research/18/k/trickbot-shows-off-new-trick-password-grabber-module.html
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 non filezilla process $process_name$ with $process_id$ accessed FileZilla XML config files on host $dest$
    risk_objects:
        - field: dest
          type: system
          score: 20
    threat_objects:
        - field: process_name
          type: process_name
tags:
    analytic_story:
        - Quasar RAT
    asset_type: Endpoint
    mitre_attack_id:
        - T1552.001
    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/attack_techniques/T1552.001/file_xml_config/filezilla_obj.log
          source: XmlWinEventLog:Security
          sourcetype: XmlWinEventLog