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-----BEGIN PGP SIGNED MESSAGE----- =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2001.281 -- Cisco Security Advisory VPN 3000 Concentrator IP Options Vulnerability 12 July 2001 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Cisco VPN 3000 series concentrators Vendor: Cisco Systems Operating System: Releases prior to 2.5.2 (F) Impact: Denial of Service Access Required: Remote Ref: ESB-2001.125 - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- Cisco Security Advisory: VPN 3000 Concentrator IP Options Vulnerability ============================================================================= Revision 1.0 For Public Release 2001 April 12 at 1500 UTC ------------------------------------------------------------------------ Summary ======= If a crafted IP packet, with an invalid IP Option setting is transmitted to a VPN 3000 series concentrator on the same network segment (no routers in between), it can cause the VPN 3000 series concentrator to hang with a 100% CPU Utilization. The concentrator would then have to be reset. After rebooting, the equipment would function normally until the crafted IP packet is received again. The defect can be exploited to produce a denial of service (DoS) attack. The vulnerability is described in Cisco bug id CSCds92460. This notice will be posted at http://www.cisco.com/warp/public/707/vpn3k-ipoptions-vuln-pub.shtml Affected Products ================= Cisco VPN 3000 series concentrators running software releases up to but not including revision 2.5.2 (F) are affected by this vulnerability. This series includes models 3005, 3015, 3030, 3060, and 3080. Any VPN 3000 series concentrators running revision 2.5.2 (F) or later are unaffected by this vulnerability. This vulnerability does not affect the VPN 5000 series concentrators. No other Cisco product is known to be affected by this vulnerability. To determine if a Cisco VPN 3000 series concentrator is running affected software, check the revision via the web interface or the console menu. Details ======= If a crafted IP packet, with an invalid IP Option setting, is transmitted to a VPN 3000 series concentrator on the same network segment (no routers in between), on either the Inside or the Outside interface, it can cause the VPN 3000 series concentrator to hang with a 100 % CPU Utilization. The concentrator would then have to be reset via the console port as no SNMP or HTTP remote management control would be possible. After rebooting, the equipment would function normally until the crafted IP packet is received again. In order to exploit this vulnerability the attacker must be on the same network segment as the concentrator without any routers in between. A crafted IP packet traversing a router would typically get its invalid IP Options dropped and would not be able to affect the VPN 3000 series concentrator. The vulnerability is documented as Cisco bug id CSCds92460. Impact ====== When this crafted IP packet is received by the VPN 3000 series concentrator, the concentrator will stop passing traffic and will not respond to any management inquiries via SNMP, Telnet or HTTP. However management via the console port is possible. For VPN 3000 series concentrator models 3015, 3030, 3060, and 3080 the CPU Utilization bar graph indicator on the front panel will go to 100%. Software Versions and Fixes =========================== The vulnerability has been fixed in revision 2.5.2 (E) code. The fix will be carried forward into all future releases. However due to the advisory at http://www.cisco.com/warp/public/707/vpn3k-telnet-vuln-pub.shtml the recommended revision to upgrade to is 2.5.2 (F) Upgrade can be done via the remote software upgrade feature using the VPN 3000 series concentrator's web based management interface. Obtaining Fixed Software ======================== Cisco is offering free software upgrades to remedy this vulnerability for all affected customers. Customers with service contracts may upgrade to any software release. Customers may install only the feature sets they have purchased. Fixed software is currently available. Customers with contracts should obtain upgraded software through their regular update channels. For most customers, this means that upgrades should be obtained via Cisco's Software Center at http://www.cisco.com/. Customers without contracts or warranty should get their upgrades by contacting the Cisco Technical Assistance Center (TAC) as shown below: * (800) 553-2447 (toll-free in 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 instructions and e-mail addresses for use in various languages. 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. Please do not contact either "psirt@cisco.com" or "security-alert@cisco.com" for software upgrades; faster results will be obtained by contacting the TAC directly. Workarounds =========== There are no system configuration workarounds. Please upgrade to revision 2.5.2 (F) code. Exploitation and Public Announcements ===================================== The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerabilities described in this advisory. This was reported to Cisco by a customer who accidentally discovered this vulnerability. Status of This Notice: FINAL ============================ This is a final field 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. Distribution ============ This notice will be posted on Cisco's Worldwide Web site at http://www.cisco.com/warp/public/707/vpn3k-ipoptions-vuln-pub.shtml. In addition to Worldwide Web posting, a text version of this notice will be clear-signed with the Cisco PSIRT PGP key and will be posted to the following e-mail and Usenet news recipients: * cust-security-announce@cisco.com * bugtraq@securityfocus.com * firewalls@lists.gnac.com * first-teams@first.org (including CERT/CC) * cisco@spot.colorado.edu * cisco-nsp@puck.nether.net * comp.dcom.sys.cisco * 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 given above for any updates. Revision History ================ Revision Number 1.0 2001-04-12 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. ------------------------------------------------------------------------ This notice is Copyright 2001 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. ------------------------------------------------------------------------ - -----BEGIN PGP SIGNATURE----- Version: PGP 7.0.1 iQEVAwUBOtXIVGiN3BRdFxkbAQGjSAgAqij7ajzNoZMcBduuvIRKVIwXQUB488y+ 8Jg8XTvkE7SZEkFsRg60qsaz0Bf+hikYleRP3qw5W8e8m3p/txLrK+KAHARQBMvV G53neWJIXDA+AXcYjD7f3pL5TEVI5Sx87JYQ12Pqzx0AfXNGqoiEVA2uBiMqGCSA 0wFNArUfsCqHnVExrdeIwFgZBONvekAg6yeEucAPWScuguf7N2id0bsSRpK1QIlq iggyynhTYvRAVsR6Zq7cA2Eo0mE0fo7RPTht7Uy/M+kFgWGszq7ebowDwI6z/qhB kmqpXZiBtm7pRzAafGzboAKTUWAv/1xPjKFYjF7bLg0DILETjTyiPA== =ZsBJ - -----END PGP SIGNATURE----- - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. 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