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CERT Coordination Center

IBM SecureWay Directory is vulnerable to denial-of-service attacks via LDAP handling code

Vulnerability Note VU#505564

Original Release Date: 2001-07-17 | Last Revised: 2002-12-12


The IBM SecureWay Directory contains vulnerabilities that may allow denial-of-service attacks, unauthorized privileged access, or both. 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.


The IBM SecureWay Directory server contains one or more buffer overflow vulnerabilities in the code that processes LDAP requests. These vulnerabilities were discovered independently by IBM using the PROTOS LDAPv3 test suite.


These vulnerabilities allow a remote attacker to crash affected SecureWay Directory servers, resulting in a denial-of-service condition. It is not known at this time whether these vulnerabilities will allow a remote attacker to execute arbitrary code. These vulnerabilities exist on the Solaris and Windows 2000 platforms but are not present under Windows NT, AIX, and AIX with SSL.


Apply a patch from your vendor

Please consult the vendor 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)

Vendor Information


IBM Affected

Notified:  June 01, 2001 Updated: May 20, 2002



Vendor Statement

IBM and Tivoli are currently investigating the details of the vulnerabilities in the various versions of the SecureWay product family.

Fixes are being implemented as these details become known.

Fixes will be posted to the download sites (IBM or Tivoli) for the affected platform. See under "Server Downloads" or "Software Downloads" for links to the fix distribution sites.

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.


IBM has provided the following details regarding these vulnerabilities:

Platform         Failed Test Cases(index#/category)       Failure Symptoms

Solaris          #136/E0 encoding exception-invalid       Server crash
                encodings for L field of BER

Solaris          #6119/O7 application exception           Server crash
                -large number of continuous
                attributes offered to attribute

Windows 2000     #452/E0 encoding exception               Server crash
                -invalid encodings for L
                field of BER encoding.

Windows 2000     #5554/O4 application exception-          Server crash
                large number of continuous
                initial substring offered to
                substring filter.

If you have feedback, comments, or additional information about this vulnerability, please send us email.

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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.

This document was written by Jeffrey P. Lanza.

Other Information

CVE IDs: CVE-2001-1309
CERT Advisory: CA-2001-18
Severity Metric: 4.96
Date Public: 2001-07-16
Date First Published: 2001-07-17
Date Last Updated: 2002-12-12 23:24 UTC
Document Revision: 36

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