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Ubuntu Security Notice USN-5863-1
February 09, 2023

linux-azure vulnerabilities
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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-azure: Linux kernel for Microsoft Azure Cloud systems

Details:

It was discovered that the NFSD implementation in the Linux kernel did not
properly handle some RPC messages, leading to a buffer overflow. A remote
attacker could use this to cause a denial of service (system crash) or
possibly execute arbitrary code. (CVE-2022-43945)

Tamás Koczka discovered that the Bluetooth L2CAP handshake implementation
in the Linux kernel contained multiple use-after-free vulnerabilities. A
physically proximate attacker could use this to cause a denial of service
(system crash) or possibly execute arbitrary code. (CVE-2022-42896)

It was discovered that the Xen netback driver in the Linux kernel did not
properly handle packets structured in certain ways. An attacker in a guest
VM could possibly use this to cause a denial of service (host NIC
availability). (CVE-2022-3643)

It was discovered that an integer overflow vulnerability existed in the
Bluetooth subsystem in the Linux kernel. A physically proximate attacker
could use this to cause a denial of service (system crash).
(CVE-2022-45934)

Update instructions:

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

Ubuntu 16.04 ESM:
   linux-image-4.15.0-1159-azure   4.15.0-1159.174~16.04.1
   linux-image-azure               4.15.0.1159.144

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-5863-1
   CVE-2022-3643, CVE-2022-42896, CVE-2022-43945, CVE-2022-45934