Detection rules › Splunk
Windows Unusual FileZilla XML Config Access
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.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Credential Access | T1552.001 Unsecured Credentials: Credentials In Files |
Event coverage
| Provider | Event | Title |
|---|---|---|
| Security-Auditing | Event ID 4663 | An attempt was made to access an object. |
Rule body splunk
name: Windows Unusual FileZilla XML Config Access
id: 47dc0426-cbe4-4253-8b86-1a983c3f9951
version: 4
creation_date: '2025-07-16'
modification_date: '2026-05-13'
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 ("$dest$") | 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: 7d
latest_offset: "0"
intermediate_findings:
entities:
- field: dest
type: system
score: 20
message: a non filezilla process $process_name$ with $process_id$ accessed FileZilla XML config files on host $dest$
threat_objects:
- field: process_name
type: process_name
analytic_story:
- Quasar RAT
asset_type: Endpoint
mitre_attack_id:
- T1552.001
product:
- Splunk Enterprise
- Splunk Enterprise Security
- Splunk Cloud
category: endpoint
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
test_type: unit
Stages and Predicates
Stage 1: 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*")
Stage 2: stats
| stats count min(_time) as firstTime max(_time) as lastTime by ObjectName ObjectType ProcessName AccessMask process_id EventCode Computer Caller_User_Name
Stage 3: rename
| rename Computer as dest Caller_User_Name as user ProcessName as process_name
Stage 4: search
| `security_content_ctime(firstTime)`
Stage 5: search
| `security_content_ctime(lastTime)`
Stage 6: search
| `windows_unusual_filezilla_xml_config_access_filter`
Exclusions
Top-level NOT(...) conjuncts: predicates this rule actively suppresses.
| Field | Kind | Excluded values |
|---|---|---|
ProcessName | in | "C:\Program Files (x86)\\FileZilla FTP Client\\filezilla.exe", "C:\\Program Files (x86)\\Microsoft OneDrive\\OneDrive.exe", "C:\\Program Files\\FileZilla FTP Client\\filezilla.exe", "C:\\Program Files\\Microsoft OneDrive\\OneDrive.exe" |
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.