Cisco Security Advisory

This section provides details on affected products.

Vulnerable Products

Products Confirmed Not Vulnerable

There are two different vulnerabilities, as described by the Bug IDs below. The first can lead to execution of an arbitrary code; the second can be used to reveal customer data.

• Bug IDs CSCdx17622 and CSCdx17683 -- By connecting to port 2002 and sending a crafted URL, it is possible to, in a less severe case, kill the CSADMIN module or, in a severe case, to execute an arbitrary user-supplied code. The functionality of authentication, authorization, and accounting (AAA) is not affected by termination of the CSADMIN module. This means that users will be able to authenticate normally. Only the administration function will be affected. Port 2002 is used by the CSADMIN module for remote administration.
  By providing a URL containing formatting symbols (for example, %s, %p), it is possible to execute a user-provided code. This technique is described in the following article: http://www.securityfocus.com/archive/1/66842 .
  
• Bug IDs CSCdx17689 and CSCdx17698 -- By using "..\.." in the URL it is possible to access data in any directory outside the Web root directory but on the same hard disk or disk partition. With this technique it is possible to access only the following file types: html, htm, class, jpg, jpeg or gif.
  Please note that an attacker must know the exact location and file name. It is not possible to browse a directory this way.
  

By exploiting the format vulnerability, an attacker may execute arbitrary code on the machine. This code will be executed in the same context as the CSADMIN process, and that is as administrator. Executing arbitrary code will lead to a total compromise of the machine.

By exploiting the directory traversal vulnerability, an attacker can gain unauthorized access to information in the following file types: html, htm, class, jpg, jpeg or gif. The main issue may be html files with hardcoded passwords or other sensitive information.

Both vulnerabilities are fixed by the patched CSAdmin.exe files available at http://www.cisco.com/pcgi-bin/tablebuild.pl/cs-acs-win . The file names are CSAdmin-patch-2.6-4-4.zip and CSAdmin-patch-3.0-1-40.zip. These patches must be applied only to releases 2.6(4.4) and 3.0.1 (build 40). If you are running any other release, you should open a case with the Cisco Technical Assistance Center (TAC) to receive a free upgrade. After upgrading to release 2.6(4.4) or 3.0.1 (build 40), you should apply the patches.

Note: To download these patches, you must be a registered user and you must be logged in. Unregistered users should refer to the instructions in the Obtaining Fixed Software section.

To install the patch, follow the procedure below while logged in as Administrator.

1. Manually stop the CSAdmin service.
   
2. Rename the <ACS-DIR>/CSAdmin/CSAdmin.exe file
   
3. Copy the patched CSAdmin.exe to <ACS-DIR>/CSAdmin.
   
4. Manually start the CSAdmin service.
   

There are no direct workarounds for these vulnerabilities. However, by exercising the standard best practices, it is possible to significantly mitigate both issues. These practices are:

• Block all unnecessary traffic on the outer network edge. This includes private IP address space (10.0.0.0, for example) and spoofed packets. This can be accomplished using routers or firewalls. For instruction on how to accomplish this with Cisco routers, please consult documents at http://www.cisco.com/en/US/tech/tk648/tk361/technologies_white_paper09186a00801afc76.shtml.
  
• Separate critical internal infrastructure from the rest of your internal network.
  

We strongly recommend that these practices are also followed when deploying Cisco ACS for Unix, even though it is not vulnerable to the mentioned issues.

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.

Both vulnerabilities were reported by Jonas Ländin and Patrik Karlsson from iXsecurity. Cisco PSIRT was made aware that an exploit program for the format vulnerability exists. This exploit is not thought to be released to the general public.

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.

This notice will be posted on Cisco's Worldwide Web site at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20020403-acs-win-web. 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.

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 Web site 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.