The source code of the Intel CoreAlder Lake BIOS has been leaked online, and the uncompressed version has a capacity of 5.9GB, which is likely to be leaked by a partner.
Netizens speculated that the code originated from 4chan. Yesterday, it was shared on GitHub, and it was withdrawn today. Someone read its source code log and saw that the release date was September 30. The author is an employee of LC Future Center. The code is still obtained through other means. .
I can’t believe: NDA-ed MSRs, for the newest CPU, what a good day… pic.twitter.com/bNitVJlkkL
— Mark Ermolov (@_markel___) October 8, 2022
It took several days to read through the entire code, but someone has found multiple references to “functional label testing” in the code, which in turn links the leak to the OEM. I heard that some of the code mentioned AMD’s CPU, which indicates that the code was tampered with after the leak. Surprisingly, one researcher found explicit references to undocumented MSRs that could pose a significant security risk.
The special register MSR (Model Specific Register) can only be accessed by privileged code such as BIOS or operating system. Vendors use them to toggle options within the CPU.
A CPU probably has several hundred MSRs, while Intel and AMD only publish more than half of the files. Undocumented MSRs are often associated with options that CPU manufacturers wish to keep secret. For example, researchers discovered an undocumented MSR within AMD K8 CPUs to enable privileged debug mode. MSR plays an important role in safety. Both Intel and AMD use the MSR option to close the Spectre hole.
Security researchers have shown that it is possible to create new exploit vulnerabilities in modern CPUs by manipulating undocumented MSRs. The circumstances in which this could happen are very complex and not necessarily what is happening now, but it is still a possibility. It is up to Intel to explain the situation and the risk to its customers.