Security, Hypocrisy and the Kernel Patching Spat
Opinion: McAfee and Symantec aren't trying to save you from kernel patch protection; they're trying to save their own business models.Its not easy being Microsoft. Not that you should feel sorry for the company, at least not usually. But it is often put in impossible positions, as McAfee and Symantec are doing now. The two companies are arguing, mostly in European papers in order to influence antitrust policy in the European Union, that security design decisions in Windows Vista are unfair to them and actually weaken system security. Their arguments are, for the most part, transparently false and self-serving. There are two main issues being bandied about, kernel patching and the Windows Security Center.
Ill focus on kernel patching here and on the Security Center in another column, although the big issues are largely the same: Microsoft has made design changes in Windows Vista that make the system more secure, but that limit the technical options for third-party products. Those third parties are unhappy.
- A common way to intercept kernel-mode application APIs is to patch the kernels system service table, a technique that I pioneered with Bryce for Windows back in 1996 when we wrote the first version of Regmon. Every kernel service thats exported for use by Windows applications has a pointer in a table thats indexed with the internal service number Windows assigns to the API. If a driver replaces an entry in the table with a pointer to its own function then the kernel invokes the driver function any time an application executes the API and the driver can control the behavior of the API.