Advisory ID: cisco-sa-20030930-ssl

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20030930-ssl

Revision 2.2

For Public Release 2003 September 30 23:30  UTC (GMT)


Contents

Summary
Affected Products
Details
Vulnerability Scoring Details
Impact
Software Versions and Fixes
Workarounds
Obtaining Fixed Software
Exploitation and Public Announcements
Status of this Notice: Final
Distribution
Revision History
Cisco Security Procedures

Summary

On September 30, 2003, new vulnerabilities in the OpenSSL leavingcisco.com implementation for SSL were announced. This is referred to as the "first" vulnerability in this document.

On November 4, 2003, another vulnerability in the OpenSSL leavingcisco.com implementation for SSL, version 0.9.6, was announced. This is referred to as the "second" vulnerability in this document.

An affected network device running an SSL server based on an affected OpenSSL implementation may be vulnerable to a Denial of Service (DoS) attack when presented with a malformed certificate by a client. The network device may be vulnerable to this vulnerability even if it is configured to not authenticate certificates from the client. There are workarounds available to mitigate the effects of these vulnerabilities.

This advisory will be posted at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20030930-ssl.

Affected Products

This section provides details on affected products.

Vulnerable Products

The following products have their SSL implementation based on the OpenSSL code and may be affected by the first OpenSSL vulnerability.

The following products have their SSL implementation based on the OpenSSL code and may be affected by the first and second OpenSSL vulnerabilities.

Products Confirmed Not Vulnerable

The following products, which implement SSL, are currently known to be not vulnerable to the OpenSSL vulnerabilities.

CatOS does not implement SSL and is not vulnerable. No other Cisco products are currently known to be affected by these vulnerabilities.

Details

An affected network device running an SSL server based on the OpenSSL implementation may be vulnerable to a Denial of Service (DoS) attack when presented with a malformed certificate by a client. The network device is vulnerable to this vulnerability even if it is configured to not authenticate certificates from the client.

More information on the first set of OpenSSL vulnerabilities is available at http://www.openssl.org/news/secadv_20030930.txt leavingcisco.com. This is referred to as the "first" vulnerability in this document.

More information on the second OpenSSL vulnerability is available at http://www.openssl.org/news/secadv_20031104.txt leavingcisco.com. This is referred to as the "second" vulnerability in this document.

Vulnerability Scoring Details

Cisco has provided scores for the vulnerabilities in this advisory based on the Common Vulnerability Scoring System (CVSS). The CVSS scoring in this Security Advisory is done in accordance with CVSS version 2.0.

CVSS is a standards-based scoring method that conveys vulnerability severity and helps determine urgency and priority of response.

Cisco has provided a base and temporal score. Customers can then compute environmental scores to assist in determining the impact of the vulnerability in individual networks.

Cisco has provided an FAQ to answer additional questions regarding CVSS at
http://www.cisco.com/web/about/security/intelligence/cvss-qandas.html .

Cisco has also provided a CVSS calculator to help compute the environmental impact for individual networks at
http://intellishield.cisco.com/security/alertmanager/cvss .


Impact

An affected network device running an SSL server based on the OpenSSL implementation may be vulnerable to a Denial of Service (DoS) attack when presented with a malformed certificate by a client regardless of whether it is configured to process client certificates or not.

Software Versions and Fixes

When considering software upgrades, also consult http://www.cisco.com/go/psirt and any subsequent advisories to determine exposure and a complete upgrade solution.

In all cases, customers should exercise caution to be certain the devices to be upgraded contain sufficient memory and that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, contact the Cisco Technical Assistance Center ("TAC") or your contracted maintenance provider for assistance.

Workarounds

The Cisco PSIRT recommends that affected users upgrade to a fixed software version of code as soon as it is available.

Cisco SIP Proxy Server (SPS) - Disable SSL/TLS functionality. One can do this using the Provisioning GUI. Log in, then select Farm/Proxies from the Configuration options. Select Advanced, and then the SIP Server Core tab. Turn the Enable TLS directive to Off.

Obtaining Fixed Software

Cisco has made free software available to address this vulnerability for affected customers. Prior to deploying software, customers should consult their maintenance provider or check the software for feature set compatibility and known issues specific to their environment.

Customers may only install and expect support for the feature sets they have purchased. By installing, downloading, accessing or otherwise using such software upgrades, customers agree to be bound by the terms of Cisco's software license terms found at http://www.cisco.com/public/sw-license-agreement.html, or as otherwise set forth at Cisco.com Downloads at http://www.cisco.com/public/sw-center/sw-usingswc.shtml.

Do not contact either "psirt@cisco.com" or "security-alert@cisco.com" for software upgrades.

Customers with Service Contracts

Customers with contracts should obtain upgraded software through their regular update channels. For most customers, this means that upgrades should be obtained through the Software Center on Cisco's worldwide website at http://www.cisco.com.

Customers using Third Party Support Organizations

Customers whose Cisco products are provided or maintained through prior or existing agreement with third-party support organizations such as Cisco Partners, authorized resellers, or service providers should contact that support organization for guidance and assistance with the appropriate course of action in regards to this advisory.

The effectiveness of any workaround or fix is dependent on specific customer situations such as product mix, network topology, traffic behavior, and organizational mission. Due to the variety of affected products and releases, customers should consult with their service provider or support organization to ensure any applied workaround or fix is the most appropriate for use in the intended network before it is deployed.

Customers without Service Contracts

Customers who purchase direct from Cisco but who do not hold a Cisco service contract and customers who purchase through third-party vendors but are unsuccessful at obtaining fixed software through their point of sale should get their upgrades by contacting the Cisco Technical Assistance Center (TAC). TAC contacts are as follows.

Have your product serial number available and give the URL of this notice as evidence of your entitlement to a free upgrade. Free upgrades for non-contract customers must be requested through the TAC.

Refer to http://www.cisco.com/warp/public/687/Directory/DirTAC.shtml for additional TAC contact information, including special localized telephone numbers and instructions and e-mail addresses for use in various languages.

Exploitation and Public Announcements

The Cisco PSIRT is not aware of any malicious use of the vulnerabilities described in this advisory at this time.

Status of this Notice: Final

THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME. CISCO EXPECTS TO UPDATE THIS DOCUMENT AS NEW INFORMATION BECOMES AVAILABLE.

A stand-alone copy or Paraphrase of the text of this document that omits the distribution URL in the following section is an uncontrolled copy, and may lack important information or contain factual errors.


Distribution

This advisory will be posted on Cisco's worldwide website at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20030930-ssl.

In addition to worldwide website posting, a text version of this advisory is clear-signed with the Cisco PSIRT PGP key having the fingerprint 8C82 5207 0CA9 ED40 1DD2 EE2A 7B31 A8CF 32B6 B590 and is posted to the following e-mail and Usenet news recipients.

Future updates of this advisory, if any, will be placed on Cisco's worldwide website, but may or may not be actively announced on mailing lists or newsgroups. Users concerned about this problem are encouraged to check the above URL for any updates.


Revision History

Revision 2.2

2004-21-Jan

Updated fixed release information and availability for multiple products.

Revision 2.1

2003-07-Nov

Clarified products that are known to be affected by the second OpenSSL vulnerability. Added CSS 11000 series (SCM only) as an affected product. Added software availability date for CSPM.

Revision 2.0

2003-04-Nov

Added information on second OpenSSL vulnerability.

Revision 1.3

2003-13-Oct

Added CSPM as affected. Updated SCA and NAM fixed software status.

Revision 1.2

2003-02-Oct

In the "Affected Products" and "Details" sections, added CSA and CTR as being affected. In the "Software Versions and Fixes" section, updated information about affected IOS images.

Revision 1.1

2003-30-Sept

Updated information about affected IOS images.

Revision 1.0

2003-30-Sept

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/web/about/security/psirt/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.