[GTER] Cisco Security Advisory: HTTP GET Vulnerability in AP1x00

Klaus Steding-Jessen jessen at nic.br
Mon Jul 28 13:39:01 -03 2003

Hash: SHA1

           Cisco Security Advisory: HTTP GET Vulnerability in AP1x00

Revision 1.0

  For Public Release 2003 July 28 16:00 UTC (GMT)



     Affected Products
     Software Versions and Fixes
     Obtaining Fixed Software
     Exploitation and Public Announcements
     Status of This Notice: FINAL
     Revision History
     Cisco Security Procedures



   A vulnerability has been reported by an external researcher in Cisco
   IOS(R) release for Cisco Aironet AP1x00 Series Wireless devices. The
   vulnerability affects only IOS-based Cisco Aironet Wireless products. The
   VxWorks based Cisco Aironet Wireless Devices are not affected. This
   vulnerability can cause the AP1x00 to reload and is documented as Cisco
   bug ID CSCeb49869 (registered customers only) (also CAN-2003-0511). There
   are workarounds available to mitigate the effects of this vulnerability.

   This advisory is posted at

   The external report can be found at
   leavingcisco.com. Although it mentions two issues only one is addressed by
   this advisory. The other issue, Cisco bug ID CSCdz29724 (registered
   customers only) (also CAN-2003-512), is present in all IOS software and is
   duplicated by the AP1x00 specific Cisco bug ID CSCeb49842 (registered
   customers only) . More details about it can be found at

Affected Products

   Only the following Cisco IOS-based wireless Access Points are affected:

   |   Hardware Model   | Software Release(s) |
   |Cisco Aironet       |12.2(4)JA,           |
   |Wireless Access     |12.2(4)JA1,          |
   |Point AP1100 series |12.2(8)JA, 12.2(11)JA|
   |Cisco Aironet       |                     |
   |Wireless Access     |12.2(8)JA, 12.2(11)JA|
   |Point AP1200 series |                     |
   |Cisco Aironet       |                     |
   |Wireless Bridge     |12.2(11)JA           |
   |AP1400 series       |                     |

   All previous VxWorks-based software releases for Cisco Aironet Access
   Point 1200 are not affected. That includes the following, and earlier,
   software releases: 11.56, 12.01T1, 12.02T1, 12.03T.

   In order to determine your software release you should log on the Access
   Point using any account available and execute the following command:

 access-point> show ver

 Cisco Internetwork Operating System Software
 IOS (tm) C1100 Software (C1100-K9W7-M), Version 12.2(8)JA, EARLY
 DEPLOYMENT RELEASE SOFTWARE (fc1)               ^^^^^^^^^
 TAC Support: http://www.cisco.com/tac
 Copyright (c) 1986-2003 by cisco Systems, Inc.

   The Cisco IOS software version is displayed in the second line of the
   output. In this example it is 12.2(8)JA.


   Sending a malformed URL to the Cisco Aironet AP1x00 can cause the device
   to reload.


   Repeated exploitation of this vulnerability can lead to a prolonged
   Denial-of-Service (DoS) of the AP1x00.

Software Versions and Fixes

   The vulnerability is fixed in the 12.2(11)JA1 version of the software for
   all Cisco Aironet AP1x00 devices.

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. 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 the Cisco Connection Online Software Center at

   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/tacpage/sw-center/sw-wireless.shtml. To access the
   software download URL, you must be a registered user and you must be
   logged in.

   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 purchase direct 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 get their upgrades by contacting the Cisco Technical
   Assistance Center (TAC). 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 at cisco.com

   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 at cisco.com" or
   "security-alert at cisco.com" for software upgrades.


   There are two workarounds for this vulnerability. One is to use
   access-class or access-list commands to limit the access to legitimate
   hosts only, and another workaround is to disable HTTP and use SSH to
   administer the Cisco Aironet Access Point.

   The example of using access-class is given here:

 ap(config)# ip http access-class 10
 ap(config)# access-list 10 permit host

   In this example, host is the only one that is allowed to access
   the AP. All other hosts are prohibited.

   To disable HTTP and enable SSH use this example:

 ap(config)# no ip http server
 ap(config)# ip domain name <your-domain>
 ap(config)# crypto key generate rsa
 The name for the keys will be: ap.your-domain
 Choose the size of the key modulus in the range of 360 to 2048 for your
  General Purpose Keys. Choosing a key modulus greater than 512 may take
  a few minutes.

 How many bits in the modulus [512]: 1024
 % Generating 1024 bit RSA keys ...[OK]
 ap(config)# line vty 0 4
 ap(config-line)# transport input ssh

   Now you can connect to the Cisco Aironet AP using SSH client from your
   computer. There are many free and commercial versions of SSH software

   In addition to the workarounds it is possible to mitigate the exposure by
   configuring ACLs on the device so that only legitimate hosts can use the
   http service. This can be done in the following way:

 access-list 111 permit tcp host host eq www

   In this example the host is the only one that is allowed to
   access the device at You will have to change host IP addresses
   and the ACL number to suit your configuration. This ACL will have to be
   applied to all interfaces and block all IP addresses assigned to the
   affected device.

Exploitation and Public Announcements

   This vulnerability is reported by Reda Zitouni from Vigilante. Their
   report can be found at

   The Cisco PSIRT is not aware of malicious use of the vulnerability
   described in this advisory.

Status of This Notice: 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 will update this

   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


   This notice will be posted on Cisco's worldwide website at .

   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 at cisco.com

     * bugtraq at securityfocus.com

     * full-disclosure at lists.netsys.com

     * first-teams at first.org (includes CERT/CC)

     * cisco at spot.colorado.edu

     * cisco-nsp at puck.nether.net

     * 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|2003-July-28 16:00 UTC  |Initial |
   |1.0     |(GMT)                   |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
   website 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


   This notice is Copyright 2003 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.

Comment: PGP Signed by Sharad Ahlawat, Cisco Systems PSIRT


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