RHEL 7 : grub2 (RHSA-2015:2623)
Medium Nessus Plugin ID 87397
SynopsisThe remote Red Hat host is missing one or more security updates.
DescriptionUpdated grub2 packages that fix one security issue and one bug are now available for Red Hat Enterprise Linux 7.
Red Hat Product Security has rated this update as having Moderate security impact. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available from the CVE link in the References section.
[Updated 27 January 2016] This advisory has been updated to document additional steps that need to be performed on BIOS-based systems after installing this update. No changes were made to the packages included in the advisory.
The grub2 packages provide version 2 of the Grand Unified Bootloader (GRUB), a highly configurable and customizable bootloader with modular architecture. The packages support a variety of kernel formats, file systems, computer architectures, and hardware devices.
A flaw was found in the way the grub2 handled backspace characters entered in username and password prompts. An attacker with access to the system console could use this flaw to bypass grub2 password protection and gain administrative access to the system.
This update also fixes the following bug :
* When upgrading from Red Hat Enterprise Linux 7.1 and earlier, a configured boot password was not correctly migrated to the newly introduced user.cfg configuration files. This could possibly prevent system administrators from changing grub2 configuration during system boot even if they provided the correct password. This update corrects the password migration script and the incorrectly generated user.cfg file. (BZ#1290089)
All grub2 users are advised to upgrade to these updated packages, which contain backported patches to correct these issues. For this update to take effect on BIOS-based machines, grub2 needs to be reinstalled as documented in the 'Reinstalling GRUB 2 on BIOS-Based Machines' section of the Red Hat Enterprise Linux 7 System Administrator's Guide linked to in the References section. No manual action is needed on UEFI-based machines.
SolutionUpdate the affected packages.