Vulnerability Note VU#336446

OpenCA libCheckSignature function fails to properly verify the signature of certificates

Overview

OpenCA may accept a signature from a certificate if the certificate's chain is trusted by the chain directory of OpenCA.

I. Description

The OpenCA PKI Development Project is a Certification Authority. A vulnerability exists in the way the libCheckSignature function compares the certificate in the database and the certificate of the signer.

From the OpenCA Security Advisory:

The comparison of the certificate in the database and the certificate of the signer was only performed on base of the serial of the certificate. The design of the function can cause the acceptance

of a signature if the chain of the signature can create a trust relationship to the chain directory of OpenCA and a certificate with a matching serial exists in the used PKI.

See the OpenCA Security Advisory for further details.

II. Impact

OpenCA may accept the signature of a certificate if the certificate's chain is trusted by the chain directory of OpenCA. This could allow a certificate from another PKI to authorize operations on the used PKI.

III. Solution

Upgrade
OpenCA version 0.9.1.7 has been released to address this vulnerability.

Apply Patch
OpenCA has supplied a patch which resolves this issue.

Systems Affected

Vendor	Status	Date Notified	Date Updated
OpenCA	Vulnerable	19-Jan-2004

References

http://www.openca.org/
http://www.openca.org/news/CAN-2004-0004.txt
http://www.secunia.com/advisories/10664/

Credit

Thanks to OpenCA for the information contained in their security advisory. OpenCA credits Alexandru Matei for discovering this vulnerability.

This document was written by Damon Morda.

Other Information

Date Public:	2004-01-16
Date First Published:	2004-01-19
Date Last Updated:	2004-01-22
CERT Advisory:
CVE-ID(s):	CAN-2004-0004
NVD-ID(s):	CAN-2004-0004
US-CERT Technical Alerts:
Metric:	1.69
Document Revision:	15

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