USN-2979-2: Linux kernel (Xenial HWE) vulnerabilities
16 May 2016
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 14.04 LTS
Several security issues were fixed in the kernel.
- linux-lts-xenial - Linux hardware enablement kernel from Xenial for Trusty
USN-2979-1 fixed vulnerabilities in the Linux kernel for Ubuntu 16.04 LTS. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 16.04 LTS for Ubuntu 14.04 LTS.
David Matlack discovered that the Kernel-based Virtual Machine (KVM) implementation in the Linux kernel did not properly restrict variable Memory Type Range Registers (MTRR) in KVM guests. A privileged user in a guest VM could use this to cause a denial of service (system crash) in the host, expose sensitive information from the host, or possibly gain administrative privileges in the host. (CVE-2016-3713)
Philip Pettersson discovered that the Linux kernel’s ASN.1 DER decoder did not properly process certificate files with tags of indefinite length. A local unprivileged attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code with administrative privileges. (CVE-2016-0758)
The problem can be corrected by updating your system to the following package versions:
- Ubuntu 14.04 LTS
- linux-image-4.4.0-22-generic - 4.4.0-22.40~14.04.1
- linux-image-4.4.0-22-generic-lpae - 4.4.0-22.40~14.04.1
- linux-image-4.4.0-22-lowlatency - 4.4.0-22.40~14.04.1
- linux-image-4.4.0-22-powerpc-e500mc - 4.4.0-22.40~14.04.1
- linux-image-4.4.0-22-powerpc-smp - 4.4.0-22.40~14.04.1
- linux-image-4.4.0-22-powerpc64-emb - 4.4.0-22.40~14.04.1
- linux-image-4.4.0-22-powerpc64-smp - 4.4.0-22.40~14.04.1
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
After a standard system update you need to reboot your computer to make all the necessary changes.
ATTENTION: Due to an unavoidable ABI change the kernel updates have been given a new version number, which requires you to recompile and reinstall all third party kernel modules you might have installed. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-generic-lts-xenial, linux-virtual, linux-powerpc), a standard system upgrade will automatically perform this as well.