Products & Services

Document ID: 13644

Advisory ID: cisco-sa-20010912-ssl-j

http://www.cisco.com/warp/public/707/cisco-sa-20010912-ssl-j.shtml

Revision 1.0

For Public Release 2001 September 12 1500 UTC (GMT)

Contents

Summary
Affected Products
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

A security vulnerability has been discovered in version 3.x of the RSA BSAFE SSL-J Software Developer Kit made by RSA Security. This vulnerability enables an attacker to establish a Secure Socket Layer (SSL) session with the server, bypassing the client authentication with a bogus client certificate. The server must have been developed using a vulnerable RSA BSAFE SSL-J Software Development Kit (SDK). Servers based on other libraries are not known to be vulnerable to this issue. For further details regarding this vulnerability, see http://www.rsasecurity.com/products/bsafe/.

Cisco Internet Content Distribution Network (iCDN) is affected by the vulnerable library. The only vulnerable version is iCDN 2.0. This vulnerability has been fixed in version 2.0.1.

No other Cisco product is vulnerable.

There is no workaround for this vulnerability.

This advisory is available at http://www.cisco.com/warp/public/707/cisco-sa-20010912-ssl-j.shtml

Affected Products

This section provides details on affected products.

Vulnerable Products

The only product affected is iCDN 2.0. iCDN 1.0 is not vulnerable because it does not contain the RSA BSAFE SSL-J library.

This vulnerability has been fixed in release 2.0.1

Products Confirmed Not Vulnerable

No other Cisco products are currently known to be affected by these vulnerabilities.

Details

SSL as a protocol has the notion of a "session", which can be loosely described as a set of security parameters (such as the "master secret") which are shared between a client and server (See RFC2246, Appendix B). The creation of a session incurs the greatest penalty in terms of cryptographic operations, so the obvious optimization is to cache the session parameters.

The problem is as follows: If an error occurs during the client-server handshake, the server might, under certain conditions, store the session's ID in the cache rather than discarding it. If the same client then attempts a second connection, the server cache will already contain the session ID and the shorter version of the SSL handshake will be performed. Consequently, the server will skip the client authentication phase and the connection will proceed as if the client had successfully authenticated.

For further details regarding this vulnerability see http://www.rsasecurity.com/products/bsafe/.

This vulnerability is documented as Cisco Bug ID CSCdu68211.

Impact

An attacker can gain the access to the server over an SSL connection. Once logged into the server, an attacker can access and change every accessible parameter of the system.

Software Versions and Fixes

The iCDN 1.0 is not vulnerable since it does not contain the vulnerable library.

iCDN 2.0.1 has fixed this vulnerability. It is based on a patched RSA BSAFE SSL-J SDK provided by RSA Security.

Workarounds

There is no workaround.

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.

• +1 800 553 2447 (toll free from within North America)
  
• +1 408 526 7209 (toll call from anywhere in the world)
  
• e-mail: tac@cisco.com
  

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

This vulnerability was discovered by Cisco. RSA Security provided the fix in a timely manner. The original RSA advisory is at: http://www.rsasecurity.com/products/bsafe/

The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability described in this advisory.

Status of This Notice: FINAL

Distribution

This advisory will be posted on Cisco's worldwide website at http://www.cisco.com/warp/public/707/cisco-sa-20010912-ssl-j.shtml.

In addition to worldwide web posting, a text version of this notice is clear-signed with the Cisco PSIRT PGP key and is posted to the following e-mail and Usenet news recipients.

• cust-security-announce@cisco.com
  
• bugtraq@securityfocus.com
  
• first-teams@first.org (includes CERT/CC)
  
• cisco@spot.colorado.edu
  
• comp.dcom.sys.cisco
  
• firewalls@lists.gnac.com
  
• Various internal Cisco mailing lists
  

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

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.