Ubuntu: 1570-1: GnuPG vulnerability
Posted by Benjamin D. Thomas   
Ubuntu GnuPG could be tricked into downloading a different key when downloadingfrom a key server.
==========================================================================
Ubuntu Security Notice USN-1570-1
September 17, 2012

gnupg, gnupg2 vulnerability
==========================================================================

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

- Ubuntu 12.04 LTS
- Ubuntu 11.10
- Ubuntu 11.04
- Ubuntu 10.04 LTS
- Ubuntu 8.04 LTS

Summary:

GnuPG could be tricked into downloading a different key when downloading
from a key server.

Software Description:
- gnupg: GNU privacy guard - a free PGP replacement
- gnupg2: GNU privacy guard - a free PGP replacement

Details:

It was discovered that GnuPG used a short ID when downloading keys from a
keyserver, even if a long ID was requested. An attacker could possibly use
this to return a different key with a duplicate short key id.

Update instructions:

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

Ubuntu 12.04 LTS:
  gnupg                           1.4.11-3ubuntu2.1
  gnupg2                          2.0.17-2ubuntu2.12.04.1

Ubuntu 11.10:
  gnupg                           1.4.11-3ubuntu1.11.10.1
  gnupg2                          2.0.17-2ubuntu2.11.10.1

Ubuntu 11.04:
  gnupg                           1.4.11-3ubuntu1.11.04.1
  gnupg2                          2.0.14-2ubuntu1.2

Ubuntu 10.04 LTS:
  gnupg                           1.4.10-2ubuntu1.1
  gnupg2                          2.0.14-1ubuntu1.4

Ubuntu 8.04 LTS:
  gnupg                           1.4.6-2ubuntu5.1
  gnupg2                          2.0.7-1ubuntu0.2

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

References:
  http://www.ubuntu.com/usn/usn-1570-1
  https://launchpad.net/bugs/1016643

Package Information:
  https://launchpad.net/ubuntu/+source/gnupg/1.4.11-3ubuntu2.1
  https://launchpad.net/ubuntu/+source/gnupg2/2.0.17-2ubuntu2.12.04.1
  https://launchpad.net/ubuntu/+source/gnupg/1.4.11-3ubuntu1.11.10.1
  https://launchpad.net/ubuntu/+source/gnupg2/2.0.17-2ubuntu2.11.10.1
  https://launchpad.net/ubuntu/+source/gnupg/1.4.11-3ubuntu1.11.04.1
  https://launchpad.net/ubuntu/+source/gnupg2/2.0.14-2ubuntu1.2
  https://launchpad.net/ubuntu/+source/gnupg/1.4.10-2ubuntu1.1
  https://launchpad.net/ubuntu/+source/gnupg2/2.0.14-1ubuntu1.4
  https://launchpad.net/ubuntu/+source/gnupg/1.4.6-2ubuntu5.1
  https://launchpad.net/ubuntu/+source/gnupg2/2.0.7-1ubuntu0.2