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Cisco Secure Access Control Server for Windows Admin Buffer Overflow Vulnerability

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Advisory ID: cisco-sa-20030423-ACS

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20030423-ACS

Revision 1.2

For Public Release 2003 April 23 08:00  UTC (GMT)

Summary

Cisco Secure ACS for Windows is vulnerable to a buffer overflow on the administration service which runs on TCP port 2002. Exploitation of this vulnerability results in a Denial of Service, and can potentially result in system administrator access. Cisco is providing repaired software, and customers are recommended to install patches or upgrade at their earliest opportunity. Workarounds can be implemented, and consist of blocking external access to port 2002 on the ACS.

This issue is documented in Cisco Bug ID CSCea51366. This issue is also being referenced in the Mitre CVE as CAN-2003-0210.

This advisory is available at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20030423-ACS.

Affected Products

Vulnerable Products

Cisco Secure ACS versions up to and including version 2.6.4 , 3.0.3, and 3.1.1 are affected by this vulnerability.

Products Confirmed Not Vulnerable

No other Cisco products are affected by this vulnerability. Specifically, Cisco Secure ACS for UNIX is NOT affected by this vulnerability.

Details

Cisco Secure ACS for Windows provides a Web-based management interface, termed CSAdmin, which listens on TCP port 2002. A buffer overflow vulnerability occurs during CSAdmin process servicing login requests. Once a sufficiently long user parameter is received by the server, this can cause the buffer overflow, which would typically result in the service hanging until it can be restarted. It is possible that a buffer overflow could be performed that would result in the compromise of the system and permit remote control of the system.

This issue is resolved by applying the patch files to repair the CSAdmin program, and will be repaired in future versions of CSAdmin.

Bug ID
CSCea51366

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

Customer installations of Cisco Secure ACS for Windows that provide unrestricted access to all ports on the server may be vulnerable to a Denial of Service, or potentially a root compromise. It is recommended that customers upgrade to repaired versions of Cisco Secure ACS, or install Cisco Secure ACS such that external access to management interfaces is eliminated or severely restricted.

Software Versions and Fixes

Fixes to the CSAdmin will be included in ACS for Windows versions 3.0.4, 3.1.2, and later, which will become available on the Cisco website. Patch files for 2.6.4, 3.0.3, and 3.1.1 are currently available on the Cisco website. Customers running versions earlier than 2.6.4, 3.0.3, or 3.1.1 will need to upgrade to those versions to apply the patch files.

The patch files that resolve this problem for specific versions are as follows:

  • ACS 3.1(1) - CSAdmin-Patch-3.1-1-27.zip (Please follow the "Note" link on the top of the page regarding strong encryption known as 3DES to download this patch)
  • ACS 3.0(3) - CSAdmin-Patch-3.0-3-6.zip
  • ACS 2.6 - CSAdmin-patch-2.6-4-4.zip

Customers can download these files at: http://www.cisco.com/pcgi-bin/tablebuild.pl/cs-acs-win.

For customers needing the patch for ACS 3.1(1), please select the link titled "Download Access Control Server for Windows Patches (Strong Cryptographic 3DES Software)".

Workarounds

It is recommended that customers patch systems, or upgrade to repaired versions of Cisco Secure ACS. Alternatively, the vulnerability can be mitigated by blocking access to the ACS on port 2002, as well as strictly limiting the access to internal hosts that have reason to connect to the ACS. This can be accomplished with access control lists on routers or firewalls.

Obtaining Fixed Software

Cisco has released free software updates that address these vulnerabilities. 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/en/US/docs/general/warranty/English/EU1KEN_.html , or as otherwise set forth at Cisco.com Downloads at http://www.cisco.com/public/sw-center/sw-usingswc.shtml .

Do not contact 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 agreements 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 do not hold a Cisco service contract, and customers who purchase through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should acquire 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

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

Refer to http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html for additional TAC contact information, including localized telephone numbers, and instructions and e-mail addresses for use in various languages.

Exploitation and Public Announcements

The Cisco PSIRT was made aware of this vulnerability by the NSFOCUS Security Team.

Cisco is unaware of malicious use of the vulnerabilities described in this advisory.

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.

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 is posted on Cisco's worldwide website at:

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20030423-ACS

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
  • first-teams@first.org
  • bugtraq@securityfocus.com
  • vulnwatch@vulnwatch.org
  • cisco@spot.colorado.edu
  • cisco-nsp@puck.nether.net
  • full-disclosure@lists.grok.org.uk
  • comp.dcom.sys.cisco@newsgate.cisco.com

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 1.0 2003-April-23 Initial public release.
Revision 1.1 2003-April-23 Clarified location of 3.1(1) patch files in "Software Versions and Fixes" section
Revision 1.2 2003-May-07 Additional clarification to 3.1.1 patch location

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.