USN-3823-1: Linux kernel vulnerabilities
15 November 2018
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 12.04 ESM
Several security issues were mitigated in the Linux kernel.
- linux - Linux kernel
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)
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 - 126.96.36.199.152
- linux-image-generic-pae - 188.8.131.52.152
- linux-image-highbank - 184.108.40.206.152
- linux-image-omap - 220.127.116.11.152
- linux-image-powerpc - 18.104.22.168.152
- linux-image-powerpc-smp - 22.214.171.124.152
- linux-image-powerpc64-smp - 126.96.36.199.152
- linux-image-virtual - 188.8.131.52.152
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.