[USN-1239-1] Linux kernel (EC2) vulnerabilities

[Marc Deslauriers]

==========================================================================
Ubuntu Security Notice USN-1239-1
October 25, 2011

linux-ec2 vulnerabilities
==========================================================================

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

- Ubuntu 10.04 LTS

Summary:

Several security issues were fixed in the kernel.

Software Description:
- linux-ec2: Linux kernel for EC2

Details:

Ryan Sweat discovered that the kernel incorrectly handled certain VLAN
packets. On some systems, a remote attacker could send specially crafted
traffic to crash the system, leading to a denial of service.
(CVE-2011-1576)

Vasiliy Kulikov and Dan Rosenberg discovered that ecryptfs did not
correctly check the origin of mount points. A local attacker could exploit
this to trick the system into unmounting arbitrary mount points, leading to
a denial of service. (CVE-2011-1833)

Vasiliy Kulikov discovered that taskstats did not enforce access
restrictions. A local attacker could exploit this to read certain
information, leading to a loss of privacy. (CVE-2011-2494)

Vasiliy Kulikov discovered that /proc/PID/io did not enforce access
restrictions. A local attacker could exploit this to read certain
information, leading to a loss of privacy. (CVE-2011-2495)

Dan Rosenberg discovered that the Bluetooth stack incorrectly handled
certain L2CAP requests. If a system was using Bluetooth, a remote attacker
could send specially crafted traffic to crash the system or gain root
privileges. (CVE-2011-2497)

It was discovered that the EXT4 filesystem contained multiple off-by-one
flaws. A local attacker could exploit this to crash the system, leading to
a denial of service. (CVE-2011-2695)

Fernando Gont discovered that the IPv6 stack used predictable fragment
identification numbers. A remote attacker could exploit this to exhaust
network resources, leading to a denial of service. (CVE-2011-2699)

Christian Ohm discovered that the perf command looks for configuration
files in the current directory. If a privileged user were tricked into
running perf in a directory containing a malicious configuration file, an
attacker could run arbitrary commands and possibly gain privileges.
(CVE-2011-2905)

Time Warns discovered that long symlinks were incorrectly handled on Be
filesystems. A local attacker could exploit this with a malformed Be
filesystem and crash the system, leading to a denial of service.
(CVE-2011-2928)

Dan Kaminsky discovered that the kernel incorrectly handled random sequence
number generation. An attacker could use this flaw to possibly predict
sequence numbers and inject packets. (CVE-2011-3188)

Darren Lavender discovered that the CIFS client incorrectly handled certain
large values. A remote attacker with a malicious server could exploit this
to crash the system or possibly execute arbitrary code as the root user.
(CVE-2011-3191)

Update instructions:

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

Ubuntu 10.04 LTS:
  linux-image-2.6.32-319-ec2      2.6.32-319.39

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-1239-1
  CVE-2011-1576, CVE-2011-1833, CVE-2011-2494, CVE-2011-2495,
  CVE-2011-2497, CVE-2011-2695, CVE-2011-2699, CVE-2011-2905,
  CVE-2011-2928, CVE-2011-3188, CVE-2011-3191

Package Information:
  https://launchpad.net/ubuntu/+source/linux-ec2/2.6.32-319.39


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