=========================================================================Ubuntu Security Notice USN-3353-3
July 24, 2017

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

- Ubuntu 12.04 ESM

Summary:

Heimdal could allow unintended access to network services.

Software Description:
- heimdal: Heimdal Kerberos Network Authentication Protocol

Details:

USN-3353-1 fixed a vulnerability in Heimdal. This update provides
the corresponding updade for Ubuntu 12.04 ESM.

Original advisory details:

 Jeffrey Altman, Viktor Dukhovni, and Nicolas Williams discovered
 that Heimdal clients incorrectly trusted unauthenticated portions
 of Kerberos tickets. A remote attacker could use this to impersonate
 trusted network services or perform other attacks.

Update instructions:

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

Ubuntu 12.04 ESM:
  libkrb5-26-heimdal              1.6~git20120311.dfsg.1-2ubuntu0.2

After a standard system update you need to restart any applications
using Heimdal libraries to make all the necessary changes.

References:
  
  https://ubuntu.com/security/notices/USN-3353-1
  CVE-2017-11103