[USN-3823-1] Linux kernel vulnerabilities

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Ubuntu Security Notice USN-3823-1
November 15, 2018

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

- Ubuntu 12.04 ESM

Summary:

Several security issues were mitigated in the Linux kernel.

Software Description:
- linux: Linux kernel

Details:

It was discovered that memory present in the L1 data cache of an Intel CPU
core may be exposed to a malicious process that is executing on the CPU
core. This vulnerability is also known as L1 Terminal Fault (L1TF). A local
attacker in a guest virtual machine could use this to expose sensitive
information (memory from other guests or the host OS). (CVE-2018-3646)

It was discovered that memory present in the L1 data cache of an Intel CPU
core may be exposed to a malicious process that is executing on the CPU
core. This vulnerability is also known as L1 Terminal Fault (L1TF). A local
attacker could use this to expose sensitive information (memory from the
kernel or other processes). (CVE-2018-3620)

Update instructions:

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

Ubuntu 12.04 ESM:
linux-image-3.2.0-137-generic 3.2.0-137.183
linux-image-3.2.0-137-generic-pae 3.2.0-137.183
linux-image-3.2.0-137-highbank 3.2.0-137.183
linux-image-3.2.0-137-omap 3.2.0-137.183
linux-image-3.2.0-137-powerpc-smp 3.2.0-137.183
linux-image-3.2.0-137-powerpc64-smp 3.2.0-137.183
linux-image-3.2.0-137-virtual 3.2.0-137.183
linux-image-generic 3.2.0.137.152
linux-image-generic-pae 3.2.0.137.152
linux-image-highbank 3.2.0.137.152
linux-image-omap 3.2.0.137.152
linux-image-powerpc 3.2.0.137.152
linux-image-powerpc-smp 3.2.0.137.152
linux-image-powerpc64-smp 3.2.0.137.152
linux-image-virtual 3.2.0.137.152

Please note that the recommended mitigation for CVE-2018-3646 involves
updating processor microcode in addition to updating the kernel;
however, the kernel includes a fallback for processors that have not
received microcode updates.

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-3823-1
CVE-2018-3620, CVE-2018-3646,
https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/L1TF