From psirt@cisco.com Thu Apr 11 09:52:30 2002 From: Cisco Systems Product Security Incident Response Team To: bugtraq@securityfocus.com Cc: psirt@cisco.com Date: Tue, 9 Apr 2002 09:00:00 -0800 (PDT) Subject: Cisco Security Advisory: Aironet Telnet Vulnerability -----BEGIN PGP SIGNED MESSAGE----- Cisco Security Advisory: Aironet Telnet Vulnerability ========================================================================== Revision 1.0 For Public Release 2002 April 09 16:00 (UTC +0000) ------------------------------------------------------------------------ Please provide your feedback on this document. ------------------------------------------------------------------------ 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 ======= It is possible to cause a denial-of-service attack if Cisco Aironet products have Telnet access enabled. Telnet access is the only requirement for such an attack; there are no additional conditions. The workaround for this vulnerability is to disable Telnet access. No other Cisco product is vulnerable. This advisory is available at http://www.cisco.com/warp/public/707/Aironet-Telnet.shtml. Affected Products ================= All releases up to, but excluding, 11.21 are vulnerable. The following hardware products are affected. * Cisco Aironet Access Point 340 and 350 * Cisco Aironet Bridge 350 Products not affected are: * Cisco Aironet Bridge 340 * Cisco Aironet 4800 Series * Cisco Aironet 4500 Series and 3500 Series * Cisco Aironet 3100 Series No other Cisco products are affected. Details ======= This vulnerability is documented as Cisco Bug ID CSCdw81244. It is possible to cause Cisco Aironet products to reboot if Telnet access is enabled and a password is required for authorization. This can be accomplished by providing an invalid username and password. This vulnerability cannot be triggered via the web interface. Impact ====== By repeatedly exploiting this vulnerability an attacker can cause denial of service. Software Versions and Fixes =========================== This vulnerability is fixed in release 11.21, which is available now. Obtaining Fixed Software ======================== Cisco is offering free software upgrades to remedy 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 obtain upgraded software through their regular update channels to any software release containing the feature sets they have purchased. For most customers, 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, which should be free of charge. 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). 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. 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. Workarounds =========== The workaround is to disable Telnet access. You can accomplish this by following the link, via the web interface, path to reach the Console/Telnet Setup page: 1. On the Summary Status page, click Setup. 2. On the Setup page, click Console/Telnet in the Services section of the page. 3. On that page, click on the radio button for Disable Telnet. Note: You must use the web interface or be connected on the console since you will be unable to save your changes if you are using Telnet. After disabling Telnet, your Telnet session will be terminated. Exploitation and Public Announcements ===================================== This issue was reported to Cisco by a customer. Cisco PSIRT is not aware of any malicious exploitation or public discussion of this vulnerability. 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/Aironet-Telnet.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 given above for any updates. Revision History ================ Revision 2002-April-09 Initial Public Number 1.0 16:00 UTC +0000 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. ------------------------------------------------------------------------ -----BEGIN PGP SIGNATURE----- Version: PGP 7.0 iQEVAwUBPLMHzg/VLJ+budTTAQEo1Af9HknFMZRsXzcipOom84h9NG0AjAa5auhn f0Cen+RbfEjUPjPSNsUanwh/nkTic0qMWYuWdSItlfgMwyRO92lxxXrlSIqsRSVa l47xgaxMRi638VYI78yJX0al5gwOV9WHbtQ6AxwJYlWcX7s8Jt+lD0jdChWEs20W eJkfh5V93IDYIxhe0W+Zi8LwZqwHNk26wB2r1IjwRxncIB681ATsW7dvQJzZcZ9G ztADYljUht0dDX7WvCXXIWGh4w3u5ybzQgfeAX9UBRfTMUgPWhFJPqvSQofhIHXn AIKdR5AC74JN3jXUgA6zOb06PehTeYmblac1I5bAGqqkskOqYGebxg== =vkHb -----END PGP SIGNATURE-----