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USN-1188-1: eCryptfs vulnerabilities

9 August 2011

eCryptfs could be tricked into mounting and unmounting arbitrary locations, and possibly disclose confidential information.

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Vasiliy Kulikov and Dan Rosenberg discovered that eCryptfs incorrectly
validated permissions on the requested mountpoint. A local attacker could
use this flaw to mount to arbitrary locations, leading to privilege
escalation. (CVE-2011-1831)

Vasiliy Kulikov and Dan Rosenberg discovered that eCryptfs incorrectly
validated permissions on the requested mountpoint. A local attacker could
use this flaw to unmount to arbitrary locations, leading to a denial of
service. (CVE-2011-1832)

Vasiliy Kulikov and Dan Rosenberg discovered that eCryptfs incorrectly
validated permissions on the requested source directory. A local attacker
could use this flaw to mount an arbitrary directory, possibly leading to
information disclosure. A pending kernel update will provide the other
half of the fix for this issue. (CVE-2011-1833)

Dan Rosenberg and Marc Deslauriers discovered that eCryptfs incorrectly
handled modifications to the mtab file when an error occurs. A local
attacker could use this flaw to corrupt the mtab file, and possibly unmount
arbitrary locations, leading to a denial of service. (CVE-2011-1834)

Marc Deslauriers discovered that eCryptfs incorrectly handled keys when
setting up an encrypted private directory. A local attacker could use this
flaw to manipulate keys during creation of a new user. (CVE-2011-1835)

Marc Deslauriers discovered that eCryptfs incorrectly handled permissions
during recovery. A local attacker could use this flaw to possibly access
another user's data during the recovery process. This issue only applied to
Ubuntu 11.04. (CVE-2011-1836)

Vasiliy Kulikov discovered that eCryptfs incorrectly handled lock counters.
A local attacker could use this flaw to possibly overwrite arbitrary files.
The default symlink restrictions in Ubuntu 10.10 and 11.04 should protect
against this issue. (CVE-2011-1837)

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Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.

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Update instructions

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

Ubuntu 11.04
Ubuntu 10.10
Ubuntu 10.04

In general, a standard system update will make all the necessary changes.

References

Related notices

  • USN-1219-1: linux-image-2.6.35-30-virtual, linux-lts-backport-maverick, linux-image-2.6.35-30-server, linux-image-2.6.35-30-generic, linux-image-2.6.35-30-generic-pae
  • USN-1253-1: linux-image-2.6.32-35-386, linux-image-2.6.32-35-preempt, linux-image-2.6.32-35-versatile, linux-image-2.6.32-35-sparc64, linux, linux-image-2.6.32-35-powerpc64-smp, linux-image-2.6.32-35-generic-pae, linux-image-2.6.32-35-virtual, linux-image-2.6.32-35-generic, linux-image-2.6.32-35-server, linux-image-2.6.32-35-sparc64-smp, linux-image-2.6.32-35-ia64, linux-image-2.6.32-35-powerpc-smp, linux-image-2.6.32-35-powerpc, linux-image-2.6.32-35-lpia
  • USN-1211-1: linux-image-2.6.38-11-versatile, linux-image-2.6.38-11-server, linux, linux-image-2.6.38-11-generic, linux-image-2.6.38-11-powerpc-smp, linux-image-2.6.38-11-omap, linux-image-2.6.38-11-powerpc64-smp, linux-image-2.6.38-11-powerpc, linux-image-2.6.38-11-generic-pae, linux-image-2.6.38-11-virtual
  • USN-1202-1: linux-image-2.6.35-903-omap4, linux-ti-omap4
  • USN-1239-1: linux-ec2, linux-image-2.6.32-319-ec2
  • USN-1227-1: linux-image-2.6.35-30-virtual, linux-image-2.6.35-30-powerpc-smp, linux-image-2.6.35-30-server, linux-image-2.6.35-30-versatile, linux, linux-image-2.6.35-30-omap, linux-image-2.6.35-30-powerpc64-smp, linux-image-2.6.35-30-powerpc, linux-image-2.6.35-30-generic, linux-image-2.6.35-30-generic-pae
  • USN-1240-1: linux-image-2.6.32-219-dove, linux-mvl-dove
  • USN-1204-1: linux-image-2.6.31-610-imx51, linux-fsl-imx51
  • USN-1256-1: linux-image-2.6.38-12-virtual, linux-image-2.6.38-12-generic-pae, linux-image-2.6.38-12-generic, linux-lts-backport-natty, linux-image-2.6.38-12-server
  • USN-1245-1: linux-image-2.6.32-419-dove, linux-mvl-dove
  • USN-1212-1: linux-image-2.6.38-1209-omap4, linux-ti-omap4

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