U radu jezgre operacijskog sustava Ubuntu 11.10 otkriveno je nekoliko sigurnosnih propusta. Napadačima omogućuju izvođenje napada uskraćivanjem usluge (DoS), pokretanje proizvoljnog programskog koda, zaobilaženje pojedinih sigurnosnih ograničenja i pristup datotekama.

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Ubuntu Security Notice USN-1363-1
February 13, 2012

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

- Ubuntu 11.10

Summary:

Several security issues were fixed in the kernel.

Software Description:
- linux: Linux kernel

Details:

A flaw was found in KVM's Programmable Interval Timer (PIT). When a virtual
interrupt control is not available a local user could use this to cause a
denial of service by starting a timer. (CVE-2011-4622)

A flaw was discovered in the XFS filesystem. If a local user mounts a
specially crafted XFS image it could potential execute arbitrary code on
the system. (CVE-2012-0038)

Andy Whitcroft discovered a that the Overlayfs filesystem was not doing the
extended permission checks needed by cgroups and Linux Security Modules
(LSMs). A local user could exploit this to by-pass security policy and
access files that should not be accessible. (CVE-2012-0055)

A flaw was found in the linux kernels IPv4 IGMP query processing. A remote
attacker could exploit this to cause a denial of service. (CVE-2012-0207)

Update instructions:

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

Ubuntu 11.10:
  linux-image-3.0.0-16-generic    3.0.0-16.28
  linux-image-3.0.0-16-generic-pae  3.0.0-16.28
  linux-image-3.0.0-16-omap       3.0.0-16.28
  linux-image-3.0.0-16-powerpc    3.0.0-16.28
  linux-image-3.0.0-16-powerpc-smp  3.0.0-16.28
  linux-image-3.0.0-16-powerpc64-smp  3.0.0-16.28
  linux-image-3.0.0-16-server     3.0.0-16.28
  linux-image-3.0.0-16-virtual    3.0.0-16.28

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-1363-1
  CVE-2011-4622, CVE-2012-0038, CVE-2012-0055, CVE-2012-0207

Package Information:
  https://launchpad.net/ubuntu/+source/linux/3.0.0-16.28