The SMB signing capability in the Server Message Block protocol in Microsoft Windows 2000 and Windows XP allows attackers to disable the digital signing settings in an SMB session to force the data to be sent unsigned, then inject data into the session without detection, e.g. by modifying group policy information sent from a domain controller. Maximum Severity Rating: Moderate Recommendation: Administrators should install the patch immediately. Affected Software: Microsoft Windows 2000 Microsoft Windows XP See http://www.microsoft.com/technet/security/bulletin/ms02-070.mspx