USN-868-1: GRUB 2 vulnerability

9 December 2009

GRUB 2 vulnerability

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Releases

Packages

Details

It was discovered that GRUB 2 did not properly validate passwords. An
attacker with physical access could conduct a brute force attack and bypass
authentication by submitting a 1 character password.

Reduce your security exposure

Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.

Learn more about Ubuntu Pro

Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 9.10

In general, a standard system upgrade is sufficient to effect the
necessary changes.

Users who have upgraded from GRUB Legacy to GRUB 2 and did not run
'upgrade-from-grub-legacy' (ie those who are still using Grub Legacy to
chainload into GRUB 2) will have to run the following command (possibly
adjusting 'hd0') to update GRUB 2's on disk core image:

$ sudo grub-install --no-floppy --grub-setup=/bin/true "(hd0)"

References