USN-1233-1: Kerberos Vulnerabilities

18 October 2011

krb5 vulnerabilities

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

  • Ubuntu 11.10
  • Ubuntu 11.04
  • Ubuntu 10.10
  • Ubuntu 10.04 LTS

Summary

Several denial of service issues were fixed in the Kerberos Key Distribution Center (KDC).

Software Description

  • krb5 - MIT Kerberos Network Authentication Protocol

Details

Nalin Dahyabhai, Andrej Ota and Kyle Moffett discovered a NULL pointer dereference in the KDC LDAP backend. An unauthenticated remote attacker could use this to cause a denial of service. This issue affected Ubuntu 11.10. (CVE-2011-1527)

Mark Deneen discovered that an assert() could be triggered in the krb5_ldap_lockout_audit() function in the KDC LDAP backend and the krb5_db2_lockout_audit() function in the KDC DB2 backend. An unauthenticated remote attacker could use this to cause a denial of service. (CVE-2011-1528)

It was discovered that a NULL pointer dereference could occur in the lookup_lockout_policy() function in the KDC LDAP and DB2 backends. An unauthenticated remote attacker could use this to cause a denial of service. (CVE-2011-1529)

Update instructions

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

Ubuntu 11.10
krb5-kdc - 1.9.1+dfsg-1ubuntu1.1
krb5-kdc-ldap - 1.9.1+dfsg-1ubuntu1.1
Ubuntu 11.04
krb5-kdc - 1.8.3+dfsg-5ubuntu2.2
krb5-kdc-ldap - 1.8.3+dfsg-5ubuntu2.2
Ubuntu 10.10
krb5-kdc - 1.8.1+dfsg-5ubuntu0.8
krb5-kdc-ldap - 1.8.1+dfsg-5ubuntu0.8
Ubuntu 10.04 LTS
krb5-kdc - 1.8.1+dfsg-2ubuntu0.10
krb5-kdc-ldap - 1.8.1+dfsg-2ubuntu0.10

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

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

References