==========================================================================
Ubuntu Security Notice USN-6602-1
January 25, 2024

linux, linux-aws, linux-kvm, linux-lts-xenial vulnerabilities
==========================================================================

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

- Ubuntu 16.04 LTS (Available with Ubuntu Pro)
- Ubuntu 14.04 LTS (Available with Ubuntu Pro)

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux: Linux kernel
- linux-kvm: Linux kernel for cloud environments
- linux-aws: Linux kernel for Amazon Web Services (AWS) systems
- linux-lts-xenial: Linux hardware enablement kernel from Xenial for Trusty

Details:

Jana Hofmann, Emanuele Vannacci, Cedric Fournet, Boris Kopf, and Oleksii
Oleksenko discovered that some AMD processors could leak stale data from
division operations in certain situations. A local attacker could possibly
use this to expose sensitive information. (CVE-2023-20588)

It was discovered that a race condition existed in the Linux kernel when
performing operations with kernel objects, leading to an out-of-bounds
write. A local attacker could use this to cause a denial of service (system
crash) or execute arbitrary code. (CVE-2023-45863)

It was discovered that the CIFS network file system implementation in the
Linux kernel did not properly validate the server frame size in certain
situation, leading to an out-of-bounds read vulnerability. An attacker
could use this to construct a malicious CIFS image that, when operated on,
could cause a denial of service (system crash) or possibly expose sensitive
information. (CVE-2023-6606)

Budimir Markovic, Lucas De Marchi, and Pengfei Xu discovered that the perf
subsystem in the Linux kernel did not properly validate all event sizes
when attaching new events, leading to an out-of-bounds write vulnerability.
A local attacker could use this to cause a denial of service (system crash)
or possibly execute arbitrary code. (CVE-2023-6931)

It was discovered that the IGMP protocol implementation in the Linux kernel
contained a race condition, leading to a use-after-free vulnerability. A
local attacker could use this to cause a denial of service (system crash)
or possibly execute arbitrary code. (CVE-2023-6932)

Update instructions:

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

Ubuntu 16.04 LTS (Available with Ubuntu Pro):
   linux-image-4.4.0-1128-kvm      4.4.0-1128.138
   linux-image-4.4.0-250-generic   4.4.0-250.284
   linux-image-4.4.0-250-lowlatency  4.4.0-250.284
   linux-image-generic             4.4.0.250.256
   linux-image-generic-lts-xenial  4.4.0.250.256
   linux-image-kvm                 4.4.0.1128.125
   linux-image-lowlatency          4.4.0.250.256
   linux-image-lowlatency-lts-xenial  4.4.0.250.256
   linux-image-virtual             4.4.0.250.256
   linux-image-virtual-lts-xenial  4.4.0.250.256

Ubuntu 14.04 LTS (Available with Ubuntu Pro):
   linux-image-4.4.0-1127-aws      4.4.0-1127.133
   linux-image-4.4.0-250-generic   4.4.0-250.284~14.04.1
   linux-image-4.4.0-250-lowlatency  4.4.0-250.284~14.04.1
   linux-image-aws                 4.4.0.1127.124
   linux-image-generic-lts-xenial  4.4.0.250.217
   linux-image-lowlatency-lts-xenial  4.4.0.250.217
   linux-image-virtual-lts-xenial  4.4.0.250.217

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://ubuntu.com/security/notices/USN-6602-1
   CVE-2023-20588, CVE-2023-45863, CVE-2023-6606, CVE-2023-6931,
   CVE-2023-6932