Remote Data Protocol (RDP) version 5.0 in Microsoft Windows 2000 and RDP 5.1 in Windows XP does not encrypt the checksums of plaintext session data, which could allow a remote attacker to determine the contents of encrypted sessions via sniffing, aka "Weak Encryption in RDP Protocol."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A199
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2002/ms02-051
http://www.securityfocus.com/bid/5712
http://www.securityfocus.com/bid/5711
http://www.kb.cert.org/vuls/id/865833
http://www.iss.net/security_center/static/10122.php
http://www.iss.net/security_center/static/10121.php