Detection: Windows Default RDP File Creation By Non MSTSC Process

Updated Date: 2025-10-27 ID: 692226f1-84e3-4f63-a747-d53e65699608 Author: Teoderick Contreras, Splunk Type: Anomaly Product: Splunk Enterprise Security

Description

This detection monitors the creation or modification of the Default.rdp file by non mstsc.exe process, typically found in the user's Documents folder. This file is automatically generated or updated by the Remote Desktop Connection client (mstsc.exe) when a user initiates an RDP session. It stores connection settings such as the last-used hostname, screen size, and other preferences. The presence or update of this file strongly suggests that an RDP session has been launched from the system. Since this file is commonly overlooked, it can serve as a valuable artifact in identifying remote access activity, including potential lateral movement or attacker-controlled sessions.

Search

 1
 2| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Processes where Processes.process_name != mstsc.exe by _time span=1h Processes.action Processes.dest Processes.original_file_name Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path Processes.process Processes.process_exec Processes.process_guid Processes.process_hash Processes.process_id Processes.process_integrity_level Processes.process_name Processes.process_path Processes.user Processes.user_id Processes.vendor_product 
 3| `drop_dm_object_name(Processes)` 
 4|rename process_guid as proc_guid 
 5| join proc_guid, _time [ 
 6| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Filesystem where Filesystem.file_name=default.rdp by _time span=1h Filesystem.dest Filesystem.file_create_time Filesystem.file_name Filesystem.file_path Filesystem.process_guid 
 7| `drop_dm_object_name(Filesystem)` 
 8|rename process_guid as proc_guid 
 9| fields _time dest file_create_time file_name file_path process_name process_path process proc_guid] 
10| dedup file_create_time 
11| table dest, process_name, process, file_create_time, file_name, file_path, proc_guid 
12| `windows_default_rdp_file_creation_by_non_mstsc_process_filter`

Data Source

Name	Platform	Sourcetype	Source
Sysmon EventID 1	Windows	`'XmlWinEventLog'`	`'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'`
Sysmon EventID 11	Windows	`'XmlWinEventLog'`	`'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'`

Macros Used

Name	Value
security_content_summariesonly	`summariesonly=`summariesonly_config `allow_old_summaries=`oldsummaries_config `fillnull_value=`fillnull_config``
windows_default_rdp_file_creation_by_non_mstsc_process_filter	`search *`

windows_default_rdp_file_creation_by_non_mstsc_process_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
T1021.001	Remote Desktop Protocol	Lateral Movement

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 need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the Endpoint datamodel in the Filesystem node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.

Known False Positives

False positives will be present, filter as needed or restrict to critical assets on the perimeter.

Associated Analytic Story

Windows RDP Artifacts and Defense Evasion

Risk Based Analytics (RBA)

Risk Message:

a file related to rdp connection named as default.rdp has been identified on $dest$.

Risk Object	Risk Object Type	Risk Score	Threat Objects
dest	system	20	No Threat Objects

References

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: 1