USN-3833-1: Linux kernel (AWS) vulnerabilities
linux-aws vulnerabilities
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 18.04 LTS
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.
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