USN-3823-1: Linux kernel vulnerabilities

15 November 2018

linux vulnerabilities

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

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

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