An Autralian security researcher, Peter Kleissner, has developed "Stoned Lite" bootkit designed to infect the Windows 8 MBR. The bootkit specifically demonstrates of how the User Account Control (UAC) in Windows 8 Developer Preview can be defeated.
With Windows 8, Microsoft plans on including a variety of new security features, starting with the UEFI-based secure boot, which is mandatory for all OEMs who plan on being UEFI-certified.
Kleissner, however, proves that there still are some flaws in Microsoft's products, and that the company should consider adding more security features into the mix. It was also developed so as to patch the password validation function, thus enabling the use of any password with any account.
The bootkit will store components outside the normal file system, and will have startup files hooked before Windows actually starts. And, remains active in the memory, and can be launched from an USB drive or even from a CD.
Kleissner on November 25th at Malcon 2011, presented "The Art of Bootkit Development" presentation that features his new bootkit "Stoned Lite" that attacks Windows 8 Developer Preview.