Vulnerability Note VU#865833

Microsoft Windows Remote Desktop Protocol (RDP) uses weak algorithm for encrypting packets

RDP is based on, and is an extension of, the T.120 protocol family standards. It is a multichannel-capable protocol that allows for separate virtual channels for carrying device communication and presentation data from the server, as well as encrypted client mouse and keyboard data.

An attacker would need the ability to capture an RDP session in order to exploit this vulnerability. In most cases, this would require that the attacker have physical access to the network media.

Because encryption keys are negotiated on a per-session basis, a successful attack would allow an attacker to decrypt only a single session and not multiple sessions. Thus, the attacker would need to conduct a separate cryptanalytic attack against each session he or she wished to compromise.

Systems Affected

http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/bulletin/MS02-051.asp
http://msdn.microsoft.com/library/en-us/termserv/termserv/using_terminal_services_virtual_channels.asp
http://www.microsoft.com/windows2000/techinfo/howitworks/terminal/rdpfandp.asp
http://link.springer.de/link/service/series/0558/bibs/2139/21390310.htm
http://www.ietf.org/rfc/rfc2104.txt

Credit

Ben Cohen & Pete Chown of Skygate Technology Ltd. discovered this vulnerability.

This document was written by Ian A Finlay.

Other Information

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