Threatpost posted a news story that the TDL4 rootkit bypasses the Windows code-signing protection

In recent versions of Windows, specifically Vista and Windows 7, Microsoft has introduced a number of new security features designed to prevent malicious code from running. But attackers are continually finding new ways around those protections, and the latest example is a rootkit that can bypass the Windows driver-signing protection.

  TDL4 Rootkit Bypasses Windows Code-Signing Protection