Ubuntu Security Notice 2317-1 - Eric W. Biederman discovered a flaw with the mediation of mount flags in the Linux kernel's user namespace subsystem. An unprivileged user could exploit this flaw to by-pass mount restrictions, and potentially gain administrative privileges. Kenton Varda discovered a flaw with read-only bind mounds when used with user namespaces. An unprivileged local user could exploit this flaw to gain full write privileges to a mount that should be read only. Various other issues were also addressed.
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Ubuntu Security Notice USN-2317-1
August 18, 2014
linux-lts-trusty vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 12.04 LTS
Summary:
Several security issues were fixed in the kernel.
Software Description:
- linux-lts-trusty: Linux hardware enablement kernel from Trusty
Details:
Eric W. Biederman discovered a flaw with the mediation of mount flags in
the Linux kernel's user namespace subsystem. An unprivileged user could
exploit this flaw to by-pass mount restrictions, and potentially gain
administrative privileges. (CVE-2014-5207)
Kenton Varda discovered a flaw with read-only bind mounds when used with
user namespaces. An unprivileged local user could exploit this flaw to gain
full write privileges to a mount that should be read only. (CVE-2014-5206)
Update instructions:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 12.04 LTS:
linux-image-3.13.0-34-generic 3.13.0-34.60~precise1
linux-image-3.13.0-34-generic-lpae 3.13.0-34.60~precise1
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. If
you use linux-restricted-modules, you have to update that package as
well to get modules which work with the new kernel version. Unless you
manually uninstalled the standard kernel metapackages (e.g. linux-generic,
linux-server, linux-powerpc), a standard system upgrade will automatically
perform this as well.
References:
http://www.ubuntu.com/usn/usn-2317-1
CVE-2014-5206, CVE-2014-5207
Package Information:
https://launchpad.net/ubuntu/+source/linux-lts-trusty/3.13.0-34.60~precise1