Ubuntu Security Notice USN-2701-1
30th July, 2015
linux-lts-trusty vulnerabilities
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
Andy Lutomirski discovered a flaw in the Linux kernel’s handling of nested
NMIs (non-maskable interrupts). An unprivileged local user could exploit
this flaw to cause a denial of service (system crash) or potentially
escalate their privileges. (CVE-2015-3290)
Andy Lutomirski discovered a flaw that allows user to cause the Linux
kernel to ignore some NMIs (non-maskable interrupts). A local unprivileged
user could exploit this flaw to potentially cause the system to miss
important NMIs resulting in unspecified effects. (CVE-2015-3291)
Andy Lutomirski and Petr Matousek discovered that an NMI (non-maskable
interrupt) that interrupts userspace and encounters an IRET fault is
incorrectly handled by the Linux kernel. An unprivileged local user could
exploit this flaw to cause a denial of service (kernel OOPs), corruption,
or potentially escalate privileges on the system. (CVE-2015-5157)
Update instructions
The problem can be corrected by updating your system to the following
package version:
- Ubuntu 12.04 LTS:
-
linux-image-3.13.0-61-generic
3.13.0-61.100~precise1
-
linux-image-3.13.0-61-generic-lpae
3.13.0-61.100~precise1
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. 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.