Detection: Windows File Transfer Protocol In Non-Common Process Path

Updated Date: 2025-10-20 ID: 0f43758f-1fe9-470a-a9e4-780acc4d5407 Author: Teoderick Contreras, Splunk Type: Anomaly Product: Splunk Enterprise Security

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.

Search

 1`sysmon`
 2EventCode=3
 3NOT Image IN(
 4  "C:\\Program Files \(x86\)\\*",
 5  "C:\\Program Files\\*",
 6  "C:\\Windows\\System32\\*",
 7  "C:\\Windows\\SysWOW64\\*"
 8)
 9(
10  DestinationPortName="ftp"
11  OR
12  DestinationPort=21
13)
14
15| stats count min(_time) as firstTime
16        max(_time) as lastTime
17
18by action app dest dest_ip dest_port direction dvc protocol protocol_version
19   src src_ip src_port transport user vendor_product process_name
20   process_exec process_guid process_id
21
22| `security_content_ctime(firstTime)`
23
24| `security_content_ctime(lastTime)`
25
26| `windows_file_transfer_protocol_in_non_common_process_path_filter`

Data Source

Name	Platform	Sourcetype	Source
Sysmon EventID 3	Windows	`'XmlWinEventLog'`	`'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'`

Macros Used

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

windows_file_transfer_protocol_in_non_common_process_path_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
T1071.003	Mail Protocols	Command And Control

Command and Control

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 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.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

a process $process_name$ is having a FTP connection to $dest$ in $dest_ip$

Risk Object	Risk Object Type	Risk Score	Threat Objects
dest	system	9	No Threat Objects

References

https://malpedia.caad.fkie.fraunhofer.de/details/win.agent_tesla

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`XmlWinEventLog:Microsoft-Windows-Sysmon/Operational`	`XmlWinEventLog`
Integration	✅ Passing	Dataset	`XmlWinEventLog:Microsoft-Windows-Sysmon/Operational`	`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: 8