__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Cisco PIX Multiple Vulnerabilities [Cisco Security Advisory Revision 1.0] November 21, 2002 01:00 GMT Number N-017 ______________________________________________________________________________ PROBLEM: Two vulnerabilities exist in PIX Firewall. The first vulnerability does not delete duplicate Internet Security Authentication Key Management Protocol Security Associations (ISAKMP SAs) with the peer. The second vulnerability has a buffer overflow while doing HTTP traffic authentication. PLATFORM: All PIX Firewall units running the vulnerable releases and using the specific features are affected by these vulnerabilities as specified in the Affected Products section of Cisco's bulletin. DAMAGE: The first vulnerability can be exploited to initiate a Man-in-the-Middle attack for VPN sessions to the PIX. The second vulnerability can be exploited to initiate a Denial-of-Service attack. SOLUTION: Upgrade to fixed releases as prescribed by Cisco's bulletin. ______________________________________________________________________________ VULNERABILITY The risk is MEDIUM. In the first vulnerability an attacker must ASSESSMENT: be able to block a logged-in user's connection and establish a connection to the PIX using the same IP address as that of the user. The second vulnerability may cause the PIX to crash, thus causing a denial of service. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/n-017.shtml ORIGINAL BULLETIN: http://www.cisco.com/warp/public/707/ pix-multiple-vuln-pub.shtml ______________________________________________________________________________ [***** Start Cisco Security Advisory Revision 1.0 *****] Cisco Security Advisory: Cisco PIX Multiple Vulnerabilities Revision 1.0 For Public Release 2002 November 20 at 1600 UTC (GMT) ---------------------------------------------------------------------- Contents Summary Affected Products Details Impact Software Versions and Fixes Obtaining Fixed Software Workarounds Exploitation and Public Announcements Status of This Notice Distribution Revision History Cisco Security Procedures ---------------------------------------------------------------------- Summary The Cisco PIX Firewall provides robust, enterprise-class security services including stateful inspection firewalling, standards-based IP Security (IPsec) Virtual Private Networking (VPN), intrusion protection and much more in cost-effective, easy to deploy solutions. Two vulnerabilities have been resolved for the PIX firewall for which fixes are available. These vulnerabilities are documented as Cisco bug ID CSCdv83490 and CSCdx35823. There are no workarounds available to mitigate the effects of these vulnerabilities. This advisory will be posted at http://www.cisco.com/warp/public/707/pix-multiple-vuln-pub.shtml. Affected Products All PIX Firewall units running the vulnerable releases and using the specific features are affected by these vulnerabilities. No other Cisco products are currently known to be affected by these vulnerabilities. +-------------------------------------------------+ | DDTs-Description |Affected Release | |-------------------------------+-----------------| |CSCdv83490-While processing |6.0.3 and earlier| |initial contact notify messages|6.1.3 and earlier| |the PIX does not delete | | |duplicate Internet Security | | |Authentication Key Management | | |Protocol Security Associations | | |(ISAKMP SAs) with the peer. | | |-------------------------------+-----------------| |CSCdx35823-Buffer overflow |5.2.8 and earlier| |while doing HTTP traffic |6.0.3 and earlier| |authentication using Terminal |6.1.3 and earlier| |Access Controller Access |6.2.1 and earlier| |Control System Plus (TACACS+) | | |or Remote Authentication | | |Dial-In User Service (RADIUS). | | +-------------------------------------------------+ To determine your software revision, type show version at the command line prompt. Details CSCdv83490 When a user establishes a VPN session upon successful peer and user authentication, the PIX creates an ISAKMP SA associating the user and his IP address. If an attacker is now able to block the logged-in user's connection and establish a connection to the PIX using the same IP address as that of the user, he will be able to establish a VPN session with the PIX, using only peer authentication, provided he already has access to the peer authentication key also known as the group pre-shared key (PSK) or group password key. CSCdx35823 A user starting a connection via FTP, Telnet, or over the World Wide Web (HTTP) is prompted for their user name and password. If the user name and password are verified by the designated TACACS+ or RADIUS authentication server, the PIX Firewall unit will allow further traffic between the authentication server and the connection to interact independently through the PIX Firewall unit's "cut-through proxy" feature. The PIX may crash and reload due to a buffer overflow vulnerability while processing HTTP traffic requests for authentication using TACACS+ or RADIUS. The Internetworking Terms and Acronyms online guide can be found at http://www.cisco.com/univercd/cc/td/doc/cisintwk/ita/index.htm. The Cisco Systems Terms and Acronyms online guide can be found at http://www.cisco.com/univercd/cc/td/doc/cisintwk/ita/cisco12.htm. These vulnerabilities are documented in the Bug Toolkit as Bug IDs CSCdv83490 and CSCdx35823, and can be viewed after 2002 November 21 at 1600 UTC. To access this tool, you must be a registered user and you must be logged in. Impact +-------------------------------------------------+ | DDTs-Description | Impact | |-------------------------+-----------------------| |CSCdv83490-While |This vulnerability can | |processing initial |be exploited to | |contact notify messages |initiate a | |the PIX does not delete |Man-In-The-Middle | |duplicate ISAKMP SA's |attack for VPN sessions| |with the peer. |to the PIX. | |-------------------------+-----------------------| |CSCdx35823 - Buffer |This vulnerability can | |overflow while doing HTTP|be exploited to | |traffic authentication |initiate a | |using TACACS+ or RADIUS. |Denial-of-Service | | |attack. | +-------------------------------------------------+ Software Versions and Fixes +-------------------------------------------------+ | DDTs-Description |Fixed Releases| |----------------------------------+--------------| |CSCdv83490-While processing |6.0.4 and | |initial contact notify messages |later | |the PIX does not delete duplicate |6.1.4 and | |ISAKMP SAs with the peer. |later | | |6.2.1 and | | |later | |----------------------------------+--------------| |CSCdx35823-Buffer overflow while |5.2.9 and | |doing HTTP traffic authentication |later | |using TACACS+ or RADIUS. |6.0.4 and | | |later | | |6.1.4 and | | |later | | |6.2.2 and | | |later | +-------------------------------------------------+ The procedure to upgrade to the fixed software version is detailed at http://www.cisco.com/univercd/cc/td/doc/product/iaabu/pix/pix_sw/index.htm. Obtaining Fixed Software Cisco is offering free software upgrades to address these vulnerabilities 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 the free software upgrade identified via this advisory. For most customers with service contracts, this means that upgrades should be obtained through the Software Center on Cisco's worldwide website at http://www.cisco.com/pcgi-bin/tablebuild.pl/pix. To access the software, download URL http://www.cisco.com/pcgi-bin/tablebuild.pl/pix, you must be a registered user and you must be logged in. Customers whose Cisco products are provided or maintained through a 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 obtaining the free software upgrade(s). 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) using the contact information listed below. In these cases, customers are entitled to obtain an upgrade to a later version of the same release or as indicated by the applicable corrected software version in the Software Versions and Fixes section (noted above). 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 advisory 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 workarounds for these vulnerabilities. The Cisco PSIRT recommends that affected users upgrade to a fixed software version of code. Exploitation and Public Announcements The Cisco PSIRT is not aware of any malicious use of the vulnerabilities described in this advisory. These vulnerabilities were reported to PSIRT by Cisco engineering and customers. Status of This Advisory: FINAL This is a final advisory. Although Cisco cannot guarantee the accuracy of all statements in this advisory, all of the facts have been checked to the best of our ability. Cisco does not anticipate issuing updated versions of this advisory unless there is some material change in the facts. Should there be a significant change in the facts, Cisco may update this advisory. A stand-alone 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 advisory will be posted on Cisco's worldwide website at http://www.cisco.com/warp/public/707/pix-multiple-vuln-pub.shtml. In addition to worldwide website posting, a text version of this advisory is clear-signed with the Cisco PSIRT PGP key having the fingerprint FEB1 1B89 A64B 60BB 4770 D1CE 93D2 FF06 F236 759C and is posted to the following e-mail and Usenet news recipients: * cust-security-announce@cisco.com * bugtraq@securityfocus.com * full-disclosure@lists.netsys.com * first-teams@first.org (includes CERT/CC) * cisco-nsp@puck.nether.net * cisco@spot.colorado.edu * comp.dcom.sys.cisco * 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 +-------------------------------------------------+ | Revision | 2002-Nov-20 | Initial public release | | 1.0 | | | +-------------------------------------------------+ 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/warp/public/707/sec_incident_response.shtml. This includes instructions for press inquiries regarding Cisco security advisories. All Cisco security advisories are available at http://www.cisco.com/go/psirt. ---------------------------------------------------------------------- This advisory is Copyright 2002 by Cisco Systems, Inc. This advisory may be redistributed freely after the release date given at the top of the text, provided that redistributed copies are complete and unmodified, including all date and version information. ---------------------------------------------------------------------- [***** End Cisco Security Advisory Revision 1.0 *****] _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Cisco Systems, Inc. for the information contained in this bulletin. _______________________________________________________________________________ CIAC, the Computer Incident Advisory Capability, 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. 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