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Cisco Security Response: Multiple Vulnerabilities in OpenSSL library

Document ID: 71992

http://www.cisco.com/warp/public/707/cisco-sr-20061108-openssl.shtml

Revision 1.6

Last Updated 2007 July 25 1300 UTC (GMT)

For Public Release 2006 November 08 1600 UTC (GMT)

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Contents

Cisco Response
Additional Information
Revision History
Cisco Security Procedures

Cisco Response

This is the Cisco PSIRT response to the multiple security advisories published by The OpenSSL Project. The vulnerabilities are as follows:

As of this publication, there are no workarounds available for any of these vulnerabilities, but it may be possible to mitigate some of the exposure. This Security Response lists the status of each product or application when considered individually. However, in cases where multiple applications are running on the same computer, a vulnerability in one application or component can compromise the entire system. This compromise can then be leveraged against applications that would otherwise be unaffected. Therefore, users must consider all applications when determining their exposure to these vulnerabilities. Cisco strongly recommends that customers update all vulnerable applications and components to provide the greatest protection from the listed vulnerabilities. Cisco will update this document in the event of any changes.

Additional Information

RSA Signature Forgery

During the CRYPTO 2006 conference, which was held August 20-24, 2006, Daniel Bleichenbacher presented a method for forging RSA signatures. The attack requires two conditions to be successful:

Notes describing this attack are at http://www.imc.org/ietf-openpgp/mail-archive/msg14307.html leavingcisco.com.

The signature verification implementation vulnerability consists of improper verification of PKCS-1 padded data. Any software with this vulnerability might accept a forged signature, but only if the key that is being forged has 3 (three) as one of the exponents.

ASN.1 Denial of Service Attacks

Two vulnerabilities have been uncovered by an ASN.1 test suite developed by Dr. S. N. Henson. Both of these vulnerabilities, if exploited, can cause denial of service. The vulnerabilities are as follows:

SSL_get_shared_ciphers() buffer overflow

A specially crafted list of ciphers can be used to overrun a buffer. This vulnerability has been assigned CVE ID of CVE-2006-3738 and was discovered by Tavis Ormandy and Will Drewry from Google Security Team.

SSLv2 Client Crash

SSL server can send malformed packet during SSLv2 connection negotiation that can crash an SSL client. This vulnerability is assigned CVE ID CVE-2006-4343.

Products Affected by OpenSSL Vulnerabilities

Note: This is not a definitive list. Cisco continues to verify other products and the list will be updated accordingly. The following products are affected by the OpenSSL issues listed in this Security Response:

Products Not Affected by OpenSSL Vulnerabilities

Note:  This list is not a definitive list. Cisco continues to verify other products and the list will be updated accordingly. The following products are confirmed not vulnerable.

Workaround

SSL is predominately used for securing HTTP traffic, but is also used to secure other TCP traffic, such as SMTP, POP3, IMAP, and FTP.

Generally speaking, there is no workaround for these issues, but mitigation is possible. By blocking affected protocols at the edge of your network and by allowing only legitimate IP addresses to connect to your devices, it is possible to lower your exposure to these vulnerabilities.

Another option, which could reduce the security of your system, is to revert to non-secure variants of the protocols. In that case, you will not be affected by the vulnerabilities described here, but your traffic will be sent in clear text and, if intercepted, an adversary will be able to read it or even modify it while in transit.

Revision History

Revision 1.6

2007-July-25

Added CSCsh14665 for Cisco PIX/ASA appliances

Revision 1.5

2007-January-16

Products Affected by OpenSSL Vulnerabilities section updated for Cisco Security Agent to remove the sentence, Other supported software releases..., and updated the hotfixes.

Revision 1.4

2006-December-26

Products Affected by OpenSSL Vulnerabilites section updated for Cisco Secure ACS to list fixed software version.

Revision 1.3

2006-December-07

Products Affected by OpenSSL Vulnerabilites section updated for Cisco Call Manager, Cisco Application Control Engine Module, CiscoWorks Common Services, CiscoWorks Common Management Foundation, Cisco Application and Content Networking System (ACNS), and Cisco Wide Area Application Services (WAAS).

Revision 1.2

2006-November-17

Products Affected by OpenSSL Vulnerabilities section updated for Cisco Call Manager, Cisco Guard and Detector, Cisco Wide Area File Services Software (WAFS), and Cisco Wide Area Application Services (WAAS). One product added to the Products Not Affected by OpenSSL Vulnerabilities section.

Revision 1.1

2006-November-14

Products Affected by OpenSSL Vulnerabilities section updated to list Cisco Wireless LAN Controller software release fixes and two products added to the Products Not Affected by OpenSSL Vulnerabilities section.

Revision 1.0

2006-November-08

Initial public release.

Cisco Security Procedures

Complete information on reporting security vulnerabilities in Cisco products, obtaining assistance with security incidents, and registering to receive security information from Cisco, is available on Cisco's worldwide website at http://www.cisco.com/en/US/products/products_security_vulnerability_policy.html. This includes instructions for press inquiries regarding Cisco security notices. All Cisco security advisories are available at http://www.cisco.com/go/psirt.

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Updated: Jul 25, 2007Document ID: 71992