[USN-5580-1] Linux kernel (AWS) vulnerabilities

[Rodrigo Figueiredo Zaiden]

==========================================================================
Ubuntu Security Notice USN-5580-1
August 24, 2022

linux-aws vulnerabilities
==========================================================================

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

- Ubuntu 16.04 ESM

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux-aws: Linux kernel for Amazon Web Services (AWS) systems

Details:

It was discovered that the framebuffer driver on the Linux kernel did 
not verify size limits when changing font or screen size, leading to an 
out-of-bounds write. A local attacker could use this to cause a denial 
of service (system crash) or possibly execute arbitrary code. 
(CVE-2021-33655)

It was discovered that the virtual terminal driver in the Linux kernel 
did not properly handle VGA console font changes, leading to an 
out-of-bounds write. A local attacker could use this to cause a denial 
of service (system crash) or possibly execute arbitrary code. 
(CVE-2021-33656)

It was discovered that the Packet network protocol implementation in the
Linux kernel contained an out-of-bounds access. A remote attacker could 
use this to expose sensitive information (kernel memory). (CVE-2022-20368)

Domingo Dirutigliano and Nicola Guerrera discovered that the netfilter
subsystem in the Linux kernel did not properly handle rules that 
truncated packets below the packet header size. When such rules are in 
place, a remote attacker could possibly use this to cause a denial of 
service (system crash). (CVE-2022-36946)

Update instructions:

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

Ubuntu 16.04 ESM:
   linux-image-4.4.0-1150-aws      4.4.0-1150.165
   linux-image-aws                 4.4.0.1150.154

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-5580-1
   CVE-2021-33655, CVE-2021-33656, CVE-2022-20368, CVE-2022-36946
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