Detection: Windows Unusual FileZilla XML Config Access

Updated Date: 2025-07-16 ID: 47dc0426-cbe4-4253-8b86-1a983c3f9951 Author: Teoderick Contreras, Splunk Type: Anomaly Product: Splunk Enterprise Security

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.

Search

1`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*") 
2| stats count min(_time) as firstTime max(_time) as lastTime by  ObjectName ObjectType ProcessName AccessMask process_id EventCode Computer Caller_User_Name 
3| rename Computer as dest Caller_User_Name as user ProcessName as process_name 
4|  `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `windows_unusual_filezilla_xml_config_access_filter`

Data Source

Name	Platform	Sourcetype	Source
Windows Event Log Security 4663	Windows	`'XmlWinEventLog'`	`'XmlWinEventLog:Security'`

Macros Used

Name	Value
security_content_ctime	`convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)`
windows_unusual_filezilla_xml_config_access_filter	`search *`

windows_unusual_filezilla_xml_config_access_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
T1552.001	Credentials In Files	Credential Access

Exploitation

DE.AE

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 Risk Event	True

This configuration file applies to all detections of type anomaly. These detections will use Risk Based Alerting.

Implementation

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.

Associated Analytic Story

Quasar RAT

Risk Based Analytics (RBA)

Risk Message:

a non filezilla process $process_name$ with $process_id$ accessed FileZilla XML config files on host $dest$

Risk Object	Risk Object Type	Risk Score	Threat Objects
dest	system	40	process_name

References

https://www.trendmicro.com/en_us/research/18/k/trickbot-shows-off-new-trick-password-grabber-module.html

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`XmlWinEventLog:Security`	`XmlWinEventLog`
Integration	✅ Passing	Dataset	`XmlWinEventLog:Security`	`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