Microsoft Windows 2000 Telnet Client NTLM Authentication Patch eliminates a security vulnerability in the Telnet client which could, under certain circumstances, allow a malicious user to obtain cryptographically protected logon credentials from another user. This vulnerability could enable a malicious user to automatically request a Telnet session from an unsuspecting userls machine to the malicious userls server. As part of this session, the userls cryptographically protected NTLM (NT LanMan) authentication credentials could be passed to the malicious userls server. The malicious user could obtain these credentials and subject them to offline examination to discover the userls clear-text password. This vulnerability would only provide the malicious user with the password credentials of another user. It would not, by itself, allow the malicious user to take any actions on the userls system.