USN-1100-1: OpenLDAP vulnerabilities

31 March 2011

openldap, openldap2.3 vulnerabilities

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

  • Ubuntu 10.10
  • Ubuntu 10.04 LTS
  • Ubuntu 9.10
  • Ubuntu 8.04 LTS


An attacker could send crafted input to OpenLDAP and cause it to crash.

Software Description

  • openldap - OpenLDAP utilities
  • openldap2.3 - OpenLDAP utilities


It was discovered that OpenLDAP did not properly check forwarded authentication failures when using a slave server and chain overlay. If OpenLDAP were configured in this manner, an attacker could bypass authentication checks by sending an invalid password to a slave server. (CVE-2011-1024)

It was discovered that OpenLDAP did not properly perform authentication checks to the rootdn when using the back-ndb backend. An attacker could exploit this to access the directory by sending an arbitrary password. Ubuntu does not ship OpenLDAP with back-ndb support by default. This issue did not affect Ubuntu 8.04 LTS. (CVE-2011-1025)

It was discovered that OpenLDAP did not properly validate modrdn requests. An unauthenticated remote user could use this to cause a denial of service via application crash. (CVE-2011-1081)

Update instructions

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

Ubuntu 10.10
slapd - 2.4.23-0ubuntu3.5
Ubuntu 10.04 LTS
slapd - 2.4.21-0ubuntu5.4
Ubuntu 9.10
slapd - 2.4.18-0ubuntu1.2
Ubuntu 8.04 LTS
slapd - 2.4.9-0ubuntu0.8.04.5

To update your system, please follow these instructions:

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