6.9 - RHSA-2015:1534

Problem Description:

Updated kernel packages that fix multiple security issues and several bugs 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) - noarch, x86_64 Red Hat Enterprise Linux Client Optional (v. 7) - x86_64 Red Hat Enterprise Linux ComputeNode (v. 7) - noarch, x86_64 Red Hat Enterprise Linux ComputeNode Optional (v. 7) - x86_64 Red Hat Enterprise Linux Server (v. 7) - noarch, ppc64, ppc64le, s390x, x86_64 Red Hat Enterprise Linux Server Optional (v. 7) - ppc64, ppc64le, s390x, x86_64 Red Hat Enterprise Linux Workstation (v. 7) - noarch, x86_64 Red Hat Enterprise Linux Workstation Optional (v. 7) - x86_64

3. Description:

The kernel packages contain the Linux kernel, the core of any Linux operating system.

* An integer overflow flaw was found in the way the Linux kernel's netfilter connection tracking implementation loaded extensions. An attacker on a local network could potentially send a sequence of specially crafted packets that would initiate the loading of a large number of extensions, causing the targeted system in that network to crash. (CVE-2014-9715, Moderate)

* A stack-based buffer overflow flaw was found in the Linux kernel's early load microcode functionality. On a system with UEFI Secure Boot enabled, a local, privileged user could use this flaw to increase their privileges to the kernel (ring0) level, bypassing intended restrictions in place. (CVE-2015-2666, Moderate)

* It was found that the Linux kernel's ping socket implementation did not properly handle socket unhashing during spurious disconnects, which could lead to a use-after-free flaw. On x86-64 architecture systems, a local user able to create ping sockets could use this flaw to crash the system. On non-x86-64 architecture systems, a local user able to create ping sockets could use this flaw to escalate their privileges on the system. (CVE-2015-3636, Moderate)

* It was found that the Linux kernel's TCP/IP protocol suite implementation for IPv6 allowed the Hop Limit value to be set to a smaller value than the default one. An attacker on a local network could use this flaw to prevent systems on that network from sending or receiving network packets. (CVE-2015-2922, Low)

Red Hat would like to thank Nathan Hoad for reporting the CVE-2014-9715 issue.

This update also fixes several bugs. Refer to the following Knowledgebase article for further information:

https://access.redhat.com/articles/1474193

All kernel 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.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

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

1203712 - CVE-2015-2922 kernel: denial of service (DoS) attack against IPv6 network stacks due to improper handling of Router Advertisements. 1204722 - CVE-2015-2666 kernel: execution in the early microcode loader 1208684 - CVE-2014-9715 kernel: netfilter connection tracking extensions denial of service 1218074 - CVE-2015-3636 kernel: ping sockets: use-after-free leading to local privilege escalation