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Ubuntu Security Notice USN-2673-1
July 20, 2015

thunderbird vulnerabilities
============================================================================

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

- Ubuntu 15.04
- Ubuntu 14.10
- Ubuntu 14.04 LTS
- Ubuntu 12.04 LTS

Summary:

Several security issues were fixed in Thunderbird.

Software Description:
- thunderbird: Mozilla Open Source mail and newsgroup client

Details:

Karthikeyan Bhargavan discovered that NSS incorrectly handled state
transitions for the TLS state machine. If a remote attacker were able to
perform a man-in-the-middle attack, this flaw could be exploited to skip
the ServerKeyExchange message and remove the forward-secrecy property.
(CVE-2015-2721)

Bob Clary, Christian Holler, Bobby Holley, and Andrew McCreight discovered
multiple memory safety issues in Thunderbird. If a user were tricked in to
opening a specially crafted website in a browsing context, an attacker
could potentially exploit these to cause a denial of service via
application crash, or execute arbitrary code with the privileges of the
user invoking Thunderbird. (CVE-2015-2724)

Ronald Crane discovered multiple security vulnerabilities. If a user were
tricked in to opening a specially crafted website in a browsing context,
an attacker could potentially exploit these to cause a denial of service
via application crash, or execute arbitrary code with the privileges of
the user invoking Thunderbird. (CVE-2015-2734, CVE-2015-2735,
CVE-2015-2736, CVE-2015-2737, CVE-2015-2738, CVE-2015-2739, CVE-2015-2740)

Matthew Green discovered a DHE key processing issue in NSS where a MITM
could force a server to downgrade TLS connections to 512-bit export-grade
cryptography. An attacker could potentially exploit this to impersonate
the server. (CVE-2015-4000)

Update instructions:

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

Ubuntu 15.04:
  thunderbird                     1:31.8.0+build1-0ubuntu0.15.04.1

Ubuntu 14.10:
  thunderbird                     1:31.8.0+build1-0ubuntu0.14.10.1

Ubuntu 14.04 LTS:
  thunderbird                     1:31.8.0+build1-0ubuntu0.14.04.1

Ubuntu 12.04 LTS:
  thunderbird                     1:31.8.0+build1-0ubuntu0.12.04.1

After a standard system update you need to restart Thunderbird to make
all the necessary changes.

References:
  http://www.ubuntu.com/usn/usn-2673-1
  CVE-2015-2721, CVE-2015-2724, CVE-2015-2734, CVE-2015-2735,
  CVE-2015-2736, CVE-2015-2737, CVE-2015-2738, CVE-2015-2739,
  CVE-2015-2740, CVE-2015-4000

Package Information:
  https://launchpad.net/ubuntu/+source/thunderbird/1:31.8.0+build1-0ubuntu0.15.04.1
  https://launchpad.net/ubuntu/+source/thunderbird/1:31.8.0+build1-0ubuntu0.14.10.1
  https://launchpad.net/ubuntu/+source/thunderbird/1:31.8.0+build1-0ubuntu0.14.04.1
  https://launchpad.net/ubuntu/+source/thunderbird/1:31.8.0+build1-0ubuntu0.12.04.1