Vulnerability Note VU#935800

Multiple versions of OpenLDAP are vulnerable to denial-of-service attacks

Overview

Multiple versions of OpenLDAP contain vulnerabilities that may allow denial-of-service attacks. These vulnerabilities were revealed using the PROTOS LDAPv3 test suite and are documented in CERT Advisory CA-2001-18. If your site uses this product, the CERT/CC encourages you to follow the advice provided below.

I. Description

There are multiple vulnerabilities in the OpenLDAP implementations of the LDAP protocol. These vulnerabilities exist in the code that translates network datagrams into application-specific information.

In the encoding section of the test suite, this product failed the group that tests the handling of invalid BER length of length fields.

In the application section of the test suite, this product passed all 6685 test cases.

II. Impact

These vulnerabilities allow a remote attacker to crash affected OpenLDAP servers, resulting in a denial-of-service condition.

III. Solution

Apply a patch from your vendor

Please consult the Systems Affected section for vendor-specific information on addressing this vulnerability.

Block access to directory services at network perimeter

As a temporary measure, it is possible to limit the scope of these vulnerabilities by blocking access to directory services at the network perimeter. Please note that this workaround does not protect vulnerable products from internal attacks.

ldap 389/tcp # Lightweight Directory Access Protocol
ldap 389/udp # Lightweight Directory Access Protocol
ldaps 636/tcp # ldap protocol over TLS/SSL (was sldap)
ldaps 636/udp # ldap protocol over TLS/SSL (was sldap)

Systems Affected

Vendor	Status	Date Notified
Conectiva	Vulnerable	1-Nov-2001
Debian	Vulnerable	12-Dec-2002
MandrakeSoft	Vulnerable	12-Dec-2002
OpenLDAP	Vulnerable	16-Jul-2001
Red Hat Inc.	Vulnerable	1-Nov-2001

References

http://www.openldap.org/
http://www.ee.oulu.fi/research/ouspg/protos/testing/c06/ldapv3/
http://www.securityfocus.com/bid/3049
http://xforce.iss.net/static/6904.php

Credit

The CERT Coordination Center thanks the Oulu University Secure Programming Group for reporting these vulnerabilities to us, for their detailed technical analyses, and for their assistance in preparing this document. We would also like to thank the OpenLDAP Core Team for their assistance in preparing this document.

This document was written by Jeffrey P. Lanza.

Other Information

Date Public:	2001-07-16
Date First Published:	2001-07-16
Date Last Updated:	2002-12-12
CERT Advisory:	CA-2001-18
CVE-ID(s):	CVE-2001-0977
NVD-ID(s):	CVE-2001-0977
US-CERT Technical Alerts:
Metric:	1.77
Document Revision:	53

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