USN-3405-2: Linux kernel (Xenial HWE) vulnerabilities

28 August 2017

linux-lts-xenial vulnerabilities

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 14.04 LTS

Summary

Several security issues were fixed in the Linux kernel.

Software Description

  • linux-lts-xenial - Linux hardware enablement kernel from Xenial for Trusty

Details

USN-3405-1 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.

It was discovered that a use-after-free vulnerability existed in the POSIX message queue implementation in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2017-11176)

Huang Weller discovered that the ext4 filesystem implementation in the Linux kernel mishandled a needs-flushing-before-commit list. A local attacker could use this to expose sensitive information. (CVE-2017-7495)

It was discovered that a buffer overflow existed in the Broadcom FullMAC WLAN driver in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2017-7541)

It was discovered that the Linux kernel did not honor the UEFI secure boot mode when performing a kexec operation. A local attacker could use this to bypass secure boot restrictions. (CVE-2015-7837)

Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 14.04 LTS
linux-image-4.4.0-93-generic - 4.4.0-93.116~14.04.1
linux-image-4.4.0-93-generic-lpae - 4.4.0-93.116~14.04.1
linux-image-4.4.0-93-lowlatency - 4.4.0-93.116~14.04.1
linux-image-4.4.0-93-powerpc-e500mc - 4.4.0-93.116~14.04.1
linux-image-4.4.0-93-powerpc-smp - 4.4.0-93.116~14.04.1
linux-image-4.4.0-93-powerpc64-emb - 4.4.0-93.116~14.04.1
linux-image-4.4.0-93-powerpc64-smp - 4.4.0-93.116~14.04.1
linux-image-generic-lpae-lts-xenial - 4.4.0.93.77
linux-image-generic-lts-xenial - 4.4.0.93.77
linux-image-lowlatency-lts-xenial - 4.4.0.93.77
linux-image-powerpc-e500mc-lts-xenial - 4.4.0.93.77
linux-image-powerpc-smp-lts-xenial - 4.4.0.93.77
linux-image-powerpc64-emb-lts-xenial - 4.4.0.93.77
linux-image-powerpc64-smp-lts-xenial - 4.4.0.93.77

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-RELEASE, linux-virtual, linux-powerpc), a standard system upgrade will automatically perform this as well.

References