USN-3054-1: Linux kernel (Xenial HWE) vulnerabilities

10 August 2016

Several security issues were fixed in the kernel.

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Releases

Packages

Details

Ben Hawkes discovered an integer overflow in the Linux netfilter
implementation. On systems running 32 bit kernels, a local unprivileged
attacker could use this to cause a denial of service (system crash) or
possibly execute arbitrary code with administrative privileges.
(CVE-2016-3135)

It was discovered that the keyring implementation in the Linux kernel did
not ensure a data structure was initialized before referencing it after an
error condition occurred. A local attacker could use this to cause a denial
of service (system crash). (CVE-2016-4470)

Sasha Levin discovered that a use-after-free existed in the percpu
allocator in the Linux kernel. A local attacker could use this to cause a
denial of service (system crash) or possibly execute arbitrary code with
administrative privileges. (CVE-2016-4794)

Kangjie Lu discovered an information leak in the netlink implementation of
the Linux kernel. A local attacker could use this to obtain sensitive
information from kernel memory. (CVE-2016-5243)

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Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.

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Update instructions

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

Ubuntu 14.04

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.