__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Center ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Cisco web interface vulnerabilities in ACS for Windows April 4, 2002 20:00 GMT Number M-064 ______________________________________________________________________________ PROBLEM: Cisco Secure Access Control Server (ACS) for Windows contains two vulnerabilities. One vulnerability can lead to the execution of an arbitrary code on an ACS server and the second can lead to an unauthorized disclosure of information. PLATFORM: Cisco Secure Access Control Server for Windows version 2.6.x and ACS 3.0.1 (build 40) DAMAGE: By exploiting the format vulnerability an attacker may execute the arbitrary code on the machine. This code will be executed in the same context as Administrator. Executing arbitrary code will lead to a total compromise of the machine. By exploiting the directory traversal vulnerability an attacker can gain an unauthorized access to information in one of the following file types: html, htm, class, jpg, jpeg, or gif. SOLUTION: Apply Cisco's security patch as directed in bulletin. ______________________________________________________________________________ VULNERABILITY The risk is HIGH. The execution of arbitrary code will lead to ASSESSMENT: a total compromise of the machine. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/M064.shtml PATCHES: http://www.cisco.com/cgi-bin/tablebuild.pl/cs-acs-win ______________________________________________________________________________ [****** Start Cisco Systems Advisory ******] Summary Cisco Secure Access Control Server (ACS) for Windows contains two vulnerabilities. One vulnerability can lead to the execution of an arbitrary code on an ACS server, and the second can lead to an unauthorized disclosure of information. A patch is available for both vulnerabilities. Cisco Secure ACS for Unix is not vulnerable. No other Cisco product is vulnerable. There is no direct workaround for the vulnerabilities, but it is possible to mitigate them to a great extent. See the Workarounds section for details. This advisory is available at http://www.cisco.com/warp/public/707/ACS-Win-Web.shtml. Affected Products The affected product is Cisco Secure Access Control Server for Windows releases 2.6.x and ACS 3.0.1 (build 40). A patch is available. Cisco Secure ACS for Unix is not affected. No other Cisco products are affected. Details 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. Impact 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. Software Versions and Fixes Both vulnerabilities are fixed by the patched CSAdmin.exe files available at http://www.cisco.com/cgi-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. 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 /CSAdmin/CSAdmin.exe file 3.Copy the patched CSAdmin.exe to /CSAdmin. 4.Manually start the CSAdmin service. Obtaining Fixed Software Cisco is offering a free software patch to address this vulnerability for all affected customers. Customers may only install and expect support for the feature sets they have purchased. Customers with service contracts should contact their regular update channels to obtain any software release containing the feature sets they have purchased. For most customers with service contracts, this means that upgrades should be obtained through the Software Center on Cisco's Worldwide Web site at http://www.cisco.com. 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 assistance with the upgrade. Customers who purchased directly 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 obtain fixed software by contacting the Cisco Technical Assistance Center (TAC). In these cases, customers may only upgrade to a later version of the same release. Cisco 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 See 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. Please have your product serial number available and give the URL of this notice as evidence of your entitlement to a free upgrade. Please do not contact either "psirt@cisco.com" or "security-alert@cisco.com" for software upgrades. Workarounds 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/public/cons/isp/. 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. Exploitation and Public Announcements 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. Status of This Notice: FINAL This is a final notice. Although Cisco cannot guarantee the accuracy of all statements in this notice, all of the facts have been checked to the best of our ability. Cisco does not anticipate issuing updated versions of this notice unless there is some material change in the facts. Should there be a significant change in the facts, Cisco may update this notice. A standalone copy or paraphrase of the text of this security advisory that omits the distribution URL in the following section is an uncontrolled copy, and may lack important information or contain factual errors. Distribution This notice will be posted on Cisco's Worldwide Web site at http://www.cisco.com/warp/public/707/ACS-Win-Web.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 notice, if any, will be placed on Cisco's Worldwide Web server, but may or may not be actively announced on mailing lists or newsgroups. Users concerned about this problem are encouraged to check the URL givenabove for any updates. Revision History Revision Number 1.0 2002-April-03 16:00 UTC +0000 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 Web site at http://www.cisco.com/warp/public/707/sec_incident_response.shtml. This includes instructions for press inquiries regarding Cisco security notices. All Cisco Security Advisories are available at http://www.cisco.com/go/psirt. This notice is Copyright 2002 by Cisco Systems, Inc. This notice may be redistributed freely after the release date given at the top of the text, provided that redistributed copies are complete and unmodified, and include all date and version information. [****** End Cisco Systems Advisory ******] _____________________________________________________________________________ CIAC wishes to acknowledge the contributions of Cisco for the information contained in this bulletin. _______________________________________________________________________________ CIAC, the Computer Incident Advisory Center, is the computer security incident response team for the U.S. Department of Energy (DOE) and the emergency backup response team for the National Institutes of Health (NIH). CIAC is located at the Lawrence Livermore National Laboratory in Livermore, California. CIAC is also a founding member of FIRST, the Forum of Incident Response and Security Teams, a global organization established to foster cooperation and coordination among computer security teams worldwide. CIAC services are available to DOE, DOE contractors, and the NIH. CIAC can be contacted at: Voice: +1 925-422-8193 (7x24) FAX: +1 925-423-8002 STU-III: +1 925-423-2604 E-mail: ciac@ciac.org Previous CIAC notices, anti-virus software, and other information are available from the CIAC Computer Security Archive. World Wide Web: http://www.ciac.org/ Anonymous FTP: ftp.ciac.org PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing communities receive CIAC bulletins. If you are not part of these communities, please contact your agency's response team to report incidents. Your agency's team will coordinate with CIAC. The Forum of Incident Response and Security Teams (FIRST) is a world-wide organization. A list of FIRST member organizations and their constituencies can be obtained via WWW at http://www.first.org/. This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation or favoring by the United States Government or the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes. 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