Detection: Windows RDP Client Launched with Admin Session

Description

This detection identifies the execution of the Windows Remote Desktop Client (mstsc.exe) with the "/v" and /admin command-line arguments. The "/v" flag specifies the remote host to connect to, while the /admin flag initiates a connection to the target system’s console session, often used for administrative purposes. This combination may indicate that a user or attacker is performing privileged remote access, potentially to manage a system without disrupting existing user sessions. While such usage may be legitimate for IT administrators, it is less common in typical user behavior. Threat actors may abuse this capability during lateral movement to maintain stealthy access to high-value systems. Monitoring for this pattern can help detect interactive hands-on-keyboard activity, privilege abuse, or attempts to access critical infrastructure without leaving typical login traces associated with non-admin RDP sessions.

Search

1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name = "mstsc.exe" Processes.process = "*/v:*" Processes.process = "*/admin*" by 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| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `windows_rdp_client_launched_with_admin_session_filter`

Data Source

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

Macros Used

Annotations

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Implementation

The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the Processes node of the Endpoint data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.

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 rdp client launched with admin session on $dest$.

References

• https://medium.com/@bonguides25/how-to-clear-rdp-connections-history-in-windows-cf0ffb67f344

• https://thelocalh0st.github.io/posts/rdp/

Detection Testing

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: 2