Windows HTTP Services (aka WinHTTP) in Microsoft Windows 2000 SP4, XP SP2 and SP3, Server 2003 SP1 and SP2, Vista Gold and SP1, and Server 2008; and WinINet in Microsoft Internet Explorer 5.01 SP4, 6 SP1, 6 and 7 on Windows XP SP2 and SP3, 6 and 7 on Windows Server 2003 SP1 and SP2, 7 on Windows Vista Gold and SP1, and 7 on Windows Server 2008; allows remote web servers to capture and replay NTLM credentials, and execute arbitrary code, via vectors related to absence of a "credential-reflection protections" opt-in step, aka "Windows HTTP Services Credential Reflection Vulnerability" and "WinINet Credential Reflection Vulnerability."