Remote Desktop Protocol
|Remote Desktop Protocol|
|Platform||Windows Server 2003, Windows Server 2008, Windows Server 2012, Windows XP, Windows 7, Windows 8, Windows Server 2003 R2, Windows Server 2008 R2, Windows Server 2012 R2, Windows Vista, Windows 8.1, Windows 10|
|System Requirements||RDP service enabled, account in the Remote Desktop Users group.|
|Permissions Required||User, Remote Desktop Users|
|Data Sources||Authentication logs, Netflow/Enclave netflow, Process monitoring|
Remote desktop is a common feature in operating systems. It allows a user to log into an interactive session with a system desktop graphical user interface on a remote system. Microsoft refers to its implementation of the Remote Desktop Protocol (RDP) as Remote Desktop Services (RDS).1 There are other implementations and third-party tools that provide graphical access Remote Services similar to RDS.
Adversaries may connect to a remote system over RDP/RDS to expand access if the service is enabled and allows access to accounts with known credentials. Adversaries will likely use Credential Access techniques to acquire credentials to use with RDP. Adversaries may also use RDP in conjunction with the Accessibility Features technique for Persistence.2
- The APT1 group is known to have used RDP during operations.3
- The Axiom group is known to have used RDP during operations.4
- FIN10 has used RDP to move laterally to systems in the victim environment.5
- FIN6 used RDP to move laterally in victim networks.6
- Lazarus Group malware SierraCharlie uses RDP for propagation.7
- Patchwork attempted to use RDP to move laterally.8
- menuPass has used RDP connections to move across the victim network.9
- Cobalt Strike can start a VNC-based remote desktop server and tunnel the connection through the already established C2 channel.
Disable the RDP service if it is unnecessary, remove unnecessary accounts and groups from Remote Desktop Users groups, and enable firewall rules to block RDP traffic between network security zones. Audit the Remote Desktop Users group membership regularly. Remove the local Administrators group from the list of groups allowed to log in through RDP. Limit remote user permissions if remote access is necessary. Use remote desktop gateways and multifactor authentication for remote logins.10
Use of RDP may be legitimate, depending on the network environment and how it is used. Other factors, such as access patterns and activity that occurs after a remote login, may indicate suspicious or malicious behavior with RDP. Monitor for user accounts logged into systems they would not normally access or access patterns to multiple systems over a relatively short period of time.
- Microsoft. (n.d.). Remote Desktop Services. Retrieved June 1, 2016.
- Alperovitch, D. (2014, October 31). Malware-Free Intrusions. Retrieved November 4, 2014.
- FireEye Labs. (2014, May 20). The PLA and the 8:00am-5:00pm Work Day: FireEye Confirms DOJ’s Findings on APT1 Intrusion Activity. Retrieved November 4, 2014.
- Novetta. (n.d.). Operation SMN: Axiom Threat Actor Group Report. Retrieved November 12, 2014.
- FireEye iSIGHT Intelligence. (2017, June 16). FIN10: Anatomy of a Cyber Extortion Operation. Retrieved June 25, 2017.
- FireEye Threat Intelligence. (2016, April). Follow the Money: Dissecting the Operations of the Cyber Crime Group FIN6. Retrieved June 1, 2016.
- Novetta Threat Research Group. (2016, February 24). Operation Blockbuster: Remote Administration Tools & Content Staging Malware Report. Retrieved March 16, 2016.
- Cymmetria. (2016). Unveiling Patchwork - The Copy-Paste APT. Retrieved August 3, 2016.
- PwC and BAE Systems. (2017, April). Operation Cloud Hopper. Retrieved April 5, 2017.
- Berkeley Security, University of California. (n.d.). Securing Remote Desktop for System Administrators. Retrieved November 4, 2014.