LoFP / false positives may arise in the rdp hijacking analytic when legitimate administrators access remote sessions for maintenance or troubleshooting purposes. these activities might resemble an attacker''s attempt to hijack a disconnected session, leading to false alarms. to mitigate the risk of false positives and improve the overall security posture, organizations can implement group policy to automatically disconnect rdp sessions when they are complete. by enforcing this policy, administrators ensure that disconnected sessions are promptly terminated, reducing the window of opportunity for an attacker to hijack a session. additionally, organizations can also implement access control mechanisms and monitor the behavior of privileged accounts to further enhance security and reduce the chances of false positives in rdp hijacking detection.

Techniques

• T1543.003
• T1563
• T1563.002

Sample rules

Windows Service Create with Tscon

• source: splunk
• technicques:
  • T1563.002
  • T1563
  • T1543.003

Description

The following analytic detects potential RDP Hijacking attempts by identifying the creation of a Windows service using sc.exe with a binary path that includes tscon.exe. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process creation events and command-line arguments. This activity is significant as it indicates an attacker may be trying to hijack a disconnected RDP session, posing a risk of unauthorized access. If confirmed malicious, the attacker could gain control over an existing user session, leading to potential data theft or further system compromise.

Detection logic

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name=sc.exe Processes.process="*/dest:rdp-tcp*" by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_service_create_with_tscon_filter`