22 April 2004 - Microsoft issued the following alert:

Microsoft is aware of code available on the Internet that seeks to exploit vulnerabilities addressed as part of our April 13th security updates. We are investigating the situation to help protect our customers. Specifically, the reports detail exploit code that attempts to use the IIS PCT/SSL vulnerability on servers running Internet Information Services with the Secure Socket Layer authentication enabled. This vulnerability is addressed by bulletin [MS04-011]. Customers who have deployed MS04-011 are not at risk from this exploit code.

Microsoft considers these reports credible and serious and continues to urge all customers to immediately install the MS4-011 update as well as the other critical updates provided on April 13th.

Customers who are still evaluating and testing MS04-011 should immediately implement the workaround steps detailed for the PCT/SSL vulnerability detailed in the MS04-011. In addition, Microsoft has published a knowledge base article [KB187498] which provides additional details on SSL and how to disable PCT without applying MS04-011.

All programs that use SSL (port 443) could be affected. Although SSL is generally associated with Internet Information Services by using HTTPS and port 443, any service that implements SSL on an affected platform is likely to be vulnerable. This includes but is not limited to, Microsoft Internet Information Services 4.0, Microsoft Internet Information Services 5.0, Microsoft Internet Information Services 5.1, Microsoft Exchange Server 5.5, Microsoft Exchange Server 2000, Microsoft Exchange Server 2003, Microsoft Analysis Services 2000 (included with SQL Server 2000), and any third-party programs that use PCT. SQL Server 2000 is not vulnerable because it specifically blocks PCT connections. The affected Windows component is schannel.dll and any third-party products that leverage this Windows component are also affected.

Updated On: 15.02.17