CPU Bugs, Patches and Vulnerability

CPU bugs are a bisg problem that now people are debatingn seriously. Theo de Raadt's blog calls the Core 2 CPU line ‘buggy as hell’ and promises that the problems being patched are not innocuous bugs but security issues that will be exploited, and from userland code at that. This means that an exploit may require local access to run code, but not privileged access.

Intel's ‘Specification Update’ on these processors contains an errata section that has many of the bugs fixed. de Raadt refers to some of the errata as scary. They could lead to processor hangs or ‘unpredictable system behavior.

The fixes are in the form of microcode for the processors. Updates to the CPU microcode can be loaded at run-time, although they are not persistent. The usual way they are applied is by the BIOS at boot time, and therefore the CPU updates can be delivered as BIOS flash updates.

But updates can also be applied by the operating system, and in this case Microsoft has done just thatWriting a patch like this isn't something that companies like Microsoft can do on their own.
 
Microcode is not like regular code, and it's apt to change between different versions of the processor or even steppings. Microsoft likely got the various updates from Intel and packaged them up in a single program.
You're still better off exploiting whatever Microsoft patched last month.