Exploit/Advisories

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Ubuntu Security Notice USN-5465-1
June 08, 2022

linux, linux-aws, linux-kvm, linux-lts-xenial vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 16.04 ESM
- Ubuntu 14.04 ESM

Summary:

Several security issues were fixed in the Linux kernel.

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

Details:

It was discovered that the Linux kernel did not properly restrict access to
the kernel debugger when booted in secure boot environments. A privileged
attacker could use this to bypass UEFI Secure Boot restrictions.
(CVE-2022-21499)

Aaron Adams discovered that the netfilter subsystem in the Linux kernel did
not properly handle the removal of stateful expressions in some situations,
leading to a use-after-free vulnerability. A local attacker could use this
to cause a denial of service (system crash) or execute arbitrary code.
(CVE-2022-1966)

Jann Horn discovered that the Linux kernel did not properly enforce seccomp
restrictions in some situations. A local attacker could use this to bypass
intended seccomp sandbox restrictions. (CVE-2022-30594)

Update instructions:

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

Ubuntu 16.04 ESM:
linux-image-4.4.0-1108-kvm 4.4.0-1108.118
linux-image-4.4.0-1143-aws 4.4.0-1143.158
linux-image-4.4.0-227-generic 4.4.0-227.261
linux-image-4.4.0-227-lowlatency 4.4.0-227.261
linux-image-aws 4.4.0.1143.147
linux-image-generic 4.4.0.227.233
linux-image-kvm 4.4.0.1108.105
linux-image-lowlatency 4.4.0.227.233
linux-image-virtual 4.4.0.227.233

Ubuntu 14.04 ESM:
linux-image-4.4.0-1107-aws 4.4.0-1107.113
linux-image-4.4.0-227-generic 4.4.0-227.261~14.04.1
linux-image-4.4.0-227-lowlatency 4.4.0-227.261~14.04.1
linux-image-aws 4.4.0.1107.104
linux-image-generic-lts-xenial 4.4.0.227.197
linux-image-lowlatency-lts-xenial 4.4.0.227.197
linux-image-virtual-lts-xenial 4.4.0.227.197

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-5465-1
CVE-2022-1966, CVE-2022-21499, CVE-2022-30594

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