Synopsis
The remote Red Hat host is missing a security update for grub2.
Description
The remote Redhat Enterprise Linux 7 host has packages installed that are affected by a vulnerability as referenced in the RHSA-2015:2623 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. (CVE-2015-8370)
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.
Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.
Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.
Solution
Update the RHEL grub2 package based on the guidance in RHSA-2015:2623.
Plugin Details
File Name: redhat-RHSA-2015-2623.nasl
Agent: unix
Supported Sensors: Agentless Assessment, Continuous Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Nessus
Risk Information
Vendor
Vendor Severity: Moderate
Vector: CVSS2#AV:L/AC:M/Au:N/C:C/I:C/A:C
Vector: CVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C
Vulnerability Information
CPE: p-cpe:/a:redhat:enterprise_linux:grub2-efi, cpe:/o:redhat:enterprise_linux:7, p-cpe:/a:redhat:enterprise_linux:grub2-tools, p-cpe:/a:redhat:enterprise_linux:grub2-efi-modules, p-cpe:/a:redhat:enterprise_linux:grub2
Required KB Items: Host/local_checks_enabled, Host/RedHat/release, Host/RedHat/rpm-list, Host/cpu
Exploit Ease: No known exploits are available
Patch Publication Date: 1/27/2016
Vulnerability Publication Date: 12/16/2015