USN-940-1: Kerberos vulnerabilities

19 May 2010

krb5 vulnerabilities

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

  • Ubuntu 9.10
  • Ubuntu 9.04
  • Ubuntu 8.04 LTS
  • Ubuntu 6.06 LTS


Unauthenticated remote attackers could cause Kerberos servers to crash, leading to a denial of service.

Software Description

  • krb5 - MIT Kerberos authentication services


It was discovered that Kerberos did not correctly free memory in the GSSAPI and kdb libraries. If a remote attacker were able to manipulate an application using these libraries carefully, the service could crash, leading to a denial of service. (Only Ubuntu 6.06 LTS was affected.) (CVE-2007-5902, CVE-2007-5971, CVE-2007-5972)

Joel Johnson, Brian Almeida, and Shawn Emery discovered that Kerberos did not correctly verify certain packet structures. An unauthenticated remote attacker could send specially crafted traffic to cause the KDC or kadmind services to crash, leading to a denial of service. (CVE-2010-1320, CVE-2010-1321)

Update instructions

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

Ubuntu 9.10
krb5-admin-server - 1.7dfsg~beta3-1ubuntu0.6
krb5-kdc - 1.7dfsg~beta3-1ubuntu0.6
Ubuntu 9.04
krb5-admin-server - 1.6.dfsg.4~beta1-5ubuntu2.4
krb5-kdc - 1.6.dfsg.4~beta1-5ubuntu2.4
Ubuntu 8.04 LTS
krb5-admin-server - 1.6.dfsg.3~beta1-2ubuntu1.5
krb5-kdc - 1.6.dfsg.3~beta1-2ubuntu1.5
Ubuntu 6.06 LTS
krb5-kdc - 1.4.3-5ubuntu0.11
libkrb53 - 1.4.3-5ubuntu0.11

To update your system, please follow these instructions:

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