Microsoft Windows 2000 Gold through SP4, XP Gold through SP3, Server 2003 SP1 and SP2, Vista Gold and SP1, and Server 2008 allows remote SMB servers to execute arbitrary code on a client machine by replaying the NTLM credentials of a client user, as demonstrated by backrush, aka "SMB Credential Reflection Vulnerability."  NOTE: some reliable sources report that this vulnerability exists because of an insufficient fix for CVE-2000-0834.