Thanks for the heads up.  A little birdie told me last year that this was coming (in fact I heard that it would be out October of last year).  I can't wait to see the exploit code.

and it's been posted:

http://theinvisiblethings.blogspot.com/2009_03_01_archive.html

I finally made it through the article and the one referenced from Blackhat 2008.   While I do not fully understand Intel architecture, it seems like this is quite real, but not as scary as it sounded.  You would have to do quite a bit of recon and then write some simplistic drivers and interfaces for each function of your rootkit, such as keyboard trapping and network I/O.   Like the papers state, this makes it a very targeted attack at this point.   Looks like Intel is slowly but surely patching these vulnerabilities.   I am guessing that if they completely drop the ball here, you are going to see people writing some automated tools to exploit these.

Former33t, you would have to escalate privs from ring 3 in order to gain access to the SMM RAM areas.   There are a number of exploits in Windows and Nix that some can take advantage of for this purpose.

As I understood it, BIOS and Chipset manufacturers have to get together and stop allowing access to the SMRAM area of RAM from the OS.  Although, if I understood it correctly, one of the exploits dealt with the area of RAM where VGA memory and SMRAM memory crossed over.