7.5 - RHSA-2014:1801

Problem Description:

Updated shim packages that fix three security issues are now available for Red Hat Enterprise Linux 7.

Red Hat Product Security has rated this update as having Moderate security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Client (v. 7) - x86_64 Red Hat Enterprise Linux ComputeNode (v. 7) - x86_64 Red Hat Enterprise Linux Server (v. 7) - x86_64 Red Hat Enterprise Linux Workstation (v. 7) - x86_64

3. Description:

Shim is the initial UEFI bootloader that handles chaining to a trusted full bootloader under secure boot environments.

A heap-based buffer overflow flaw was found the way shim parsed certain IPv6 addresses. If IPv6 network booting was enabled, a malicious server could supply a crafted IPv6 address that would cause shim to crash or, potentially, execute arbitrary code. (CVE-2014-3676)

An out-of-bounds memory write flaw was found in the way shim processed certain Machine Owner Keys (MOKs). A local attacker could potentially use this flaw to execute arbitrary code on the system. (CVE-2014-3677)

An out-of-bounds memory read flaw was found in the way shim parsed certain IPv6 packets. A specially crafted DHCPv6 packet could possibly cause shim to crash, preventing the system from booting if IPv6 booting was enabled. (CVE-2014-3675)

Red Hat would like to thank the SUSE Security Team for reporting these issues.

All shim users are advised to upgrade to these updated packages, which contain backported patches to correct these issues. The system must be rebooted for this update to take effect.

4. Solution:

Before applying this update, make sure all previously released errata relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to use the Red Hat Network to apply this update are available at https://access.redhat.com/articles/11258

5. Bugs fixed (https://bugzilla.redhat.com/):

1148230 - CVE-2014-3675 shim: out-of-bounds memory read flaw in DHCPv6 packet processing 1148231 - CVE-2014-3676 shim: heap-based buffer overflow flaw in IPv6 address parsing 1148232 - CVE-2014-3677 shim: memory corruption flaw when processing Machine Owner Keys (MOKs)