NIST Publishes Draft Guidelines For Server BIOS Protection

hypnosec writes "The U.S.'s National Institute of Standards and Technology has come up with a set of proposed guidelines for security of server BIOSes— the mechanism on which most modern day computers rely during boot up. Recently quite a few instances of malware have been known to persistently infect computer systems, and cannot be removed even on OS re-installs. NIST is proposing a set of measures through which the BIOS can be made more secure and resistant to such firmware manipulating attacks. Mebromi is one such Trojan. NIST published the draft guidelines [PDF] earlier this week and has proposed four different features through which the server BIOSes can be made more secure: authenticated update mechanism; secure local update mechanism (optional); firmware integrity protections; and non-bypassability features."

Comments

Stupid and wrong

[jmorris42]

Locking the BIOS with signed updates and crap is exactly the wrong way to go. It means there will still be bugs to exploit. But the forces seeking to lock down the PC will advance yet another step under cover of security theater.

The correct solution is to give the machine a one way gate so that after POST the BIOS can't be updated, period. Electrically impossible. That would require an updater in the BIOS and either storing the extended config now flashed into the same chip with the BIOS to either go elsewhere or the flash chip to be smart enough to have a protected area and an unprotected area and only the protected area be unrevokable without a full reboot. It also should go without saying that the BIOS can't look at the unprotected area before the big switch to prevent buffer overflow attacks from getting into the BIOS while the flash is writable and/or stopping the user from invoking a clear extended data function.

A minimal rescue program in mask ROM would be gravy of course. Lets see the leet warez doodz get past that one. Wouldn't put anything past the NSA though.

Re:Stupid and wrong

[dgatwood]

Actually, it's not easy. A trojan horse can draw the same UI, write the same file to the flash drive, and a naïve user would probably dutifully follow the instructions because the user would not know any better. Your "solution" is no better than the status quo.

Allowing a power-user (someone who knows how to hold down the magic keys and isn't afraid of the BIOS UI) to install an unsigned update explicitly and manually is one thing. Such a user can be assumed to know enough about what he or she is doing to understand the risks of downloading a BIOS update from an untrusted source. Allowing unsigned BIOS updates to be installed by average users as a part of their normal day-to-day update process, however, is another thing entirely, and is a very bad idea.