==========================================================================
Ubuntu Security Notice USN-3581-1
February 22, 2018

linux vulnerabilities
==========================================================================

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

- Ubuntu 17.10

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux: Linux kernel

Details:

Mohamed Ghannam discovered that the IPv4 raw socket implementation in the
Linux kernel contained a race condition leading to uninitialized pointer
usage. A local attacker could use this to cause a denial of service or
possibly execute arbitrary code. (CVE-2017-17712)

ChunYu Wang discovered that a use-after-free vulnerability existed
in the SCTP protocol 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-2017-15115)

Mohamed Ghannam discovered a use-after-free vulnerability in the DCCP
protocol 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-2017-8824)

USN-3541-1 mitigated CVE-2017-5715 (Spectre Variant 2) for the
amd64 architecture in Ubuntu 17.10. This update provides the
compiler-based retpoline kernel mitigation for the amd64 and i386
architectures. Original advisory details:

 Jann Horn discovered that microprocessors utilizing speculative execution
 and branch prediction may allow unauthorized memory reads via sidechannel
 attacks. This flaw is known as Spectre. A local attacker could use this to
 expose sensitive information, including kernel memory. (CVE-2017-5715)

Update instructions:

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

Ubuntu 17.10:
  linux-image-4.13.0-36-generic   4.13.0-36.40
  linux-image-4.13.0-36-generic-lpae  4.13.0-36.40
  linux-image-4.13.0-36-lowlatency  4.13.0-36.40
  linux-image-generic             4.13.0.36.38
  linux-image-generic-lpae        4.13.0.36.38
  linux-image-lowlatency          4.13.0.36.38

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:
  https://usn.ubuntu.com/usn/usn-3581-1
  CVE-2017-15115, CVE-2017-17712, CVE-2017-5715, CVE-2017-8824

Package Information:
  https://launchpad.net/ubuntu/+source/linux/4.13.0-36.40