Microsoft released security bulletin MS11-100 on December 29th to address four vulnerabilities in the .NET framework. The associated patch addresses the denial of service (DoS) attack publicly disclosed at the Chaos Communication Congress on December 28th, as well as three other vulnerabilities reported through Microsoft's disclosure program.

The publicly disclosed DoS vulnerability affects most IIS servers running ASP.NET based sites. Given a single specially crafted packet can exploit the DoS vulnerability, it is likely exploit code will be publicly available and