==========================================================================
Ubuntu Security Notice USN-3742-3
August 21, 2018

linux-lts-trusty regressions
==========================================================================

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

– Ubuntu 12.04 ESM

Summary:

USN-3742-2 introduced regressions in the Linux Hardware Enablement
(HWE) kernel for Ubuntu 12.04 ESM.

Software Description:
– linux-lts-trusty: Linux hardware enablement kernel from Trusty for Precise ESM

Details:

USN-3742-2 introduced mitigations in the Linux Hardware Enablement
(HWE) kernel for Ubuntu 12.04 ESM to address L1 Terminal Fault (L1TF)
vulnerabilities (CVE-2018-3620, CVE-2018-3646). Unfortunately, the
update introduced regressions that caused kernel panics when booting
in some environments as well as preventing Java applications from
starting. This update fixes the problems.

We apologize for the inconvenience.

Original advisory details:

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)

Andrey Konovalov discovered an out-of-bounds read in the POSIX
timers subsystem in the Linux kernel. A local attacker could use
this to cause a denial of service (system crash) or expose sensitive
information. (CVE-2017-18344)

Juha-Matti Tilli discovered that the TCP implementation in the Linux kernel
performed algorithmically expensive operations in some situations when
handling incoming packets. A remote attacker could use this to cause a
denial of service. (CVE-2018-5390)

Juha-Matti Tilli discovered that the IP implementation in the Linux kernel
performed algorithmically expensive operations in some situations when
handling incoming packet fragments. A remote attacker could use this to
cause a denial of service. (CVE-2018-5391)

Update instructions:

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

Ubuntu 12.04 ESM:
linux-image-3.13.0-156-generic 3.13.0-156.206~precise1
linux-image-3.13.0-156-generic-lpae 3.13.0-156.206~precise1
linux-image-generic-lpae-lts-trusty 3.13.0.156.146
linux-image-generic-lts-trusty 3.13.0.156.146

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:
https://usn.ubuntu.com/usn/usn-3742-3
https://usn.ubuntu.com/usn/usn-3742-2
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1787127
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1787258
https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/L1TF

—–BEGIN PGP SIGNATURE—–
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=UROo
—–END PGP SIGNATURE—–
—