USN-3833-1: Linux kernel (AWS) vulnerabilities

30 November 2018

linux-aws vulnerabilities

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

Summary

Several security issues were fixed in the Linux kernel.

Software Description

• linux-aws - Linux kernel for Amazon Web Services (AWS) systems

Details

Jann Horn discovered that the Linux kernel mishandles mapping UID or GID ranges inside nested user namespaces in some situations. A local attacker could use this to bypass access controls on resources outside the namespace. (CVE-2018-18955)

Philipp Wendler discovered that the overlayfs implementation in the Linux kernel did not properly verify the directory contents permissions from within a unprivileged user namespace. A local attacker could use this to expose sensitive information (protected file names). (CVE-2018-6559)

Update instructions

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

Ubuntu 18.04 LTS

linux-image-4.15.0-1029-aws - 4.15.0-1029.30

linux-image-aws - 4.15.0.1029.29

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

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

from Ubuntu Security Notices https://ift.tt/2AFc4iq