VIGILANTe Security Watch Advisory



Name: Cisco Aironet AP1100 Valid Account Disclosure Vulnerability

Systems Affected: Tested on a Cisco Aironet AP1100 Model 1120B Series 

Wireless device.

Firmware version 12.2(4)JA and earlier.

NB : A large number of Cisco IOSes are affected by this flaw.

Severity: High Risk

Vendor URL: http://www.vigilante.com

Authors: Reda Zitouni (reda.zitouni@vigilante.com)

Date: 28th July 2003

Advisory Code: VIGILANTE-2003002



Description

***********

Cisco Aironet 1100 Series Access Point is a device manufactured by Cisco 

Systems offering a WLAN solution based on the 802.11b Wifi standard.

The Aironet Bridge is vulnerable to a Brute Force attack revealing if an 

account exists or not.



Details

*******

A flaw in firmware version 12.2(4)JA and earlier allows a malicious 

remote user to discover which accounts are valid on the targeted Cisco 

Aironet Access Point by using classical brute force techniques. 

Exploitation of this flaw is possible if the telnet service is enabled 

with authentication.



If an attacker submits an existing account as login he will be then 

prompted for the password. If not the case a ""% Login invalid" reply 

will be displayed by the server, revealing the account is not existing. 

By default on the Aironet AP1100, the 'cisco' account is set and is 

prompted for a password when submitted. That default account then allows 

an attacker to determine if this flaw on the remote device is patched or 

not. This may lead to further serious attacks.





Vendor status:

**************

Cisco was contacted June 19, 2003 and answered the same day. 5 days 

later, they told us that they would release a patch soon. The patch was 

finally released July 3, 2003. Please note that this flaw is released by 

Cisco as a Security Notice in CCO.



Vulnerability Assessment:

************************

A test case to detect this vulnerability was added to SecureScan NX in 

the upgrade package of July 28, 2003. You can see the documentation of 

this test case 15438 on SecureScan NX web site at 

http://securescannx.vigilante.com/tc/15438. 

Fix:  A firmware upgrading the Aironet IOS version to c1100-k9w7 has been 

released by Cisco. Please note that this version fixes some other bugs as 

TC 17655 (refer to release note).



Workaround:

***********

Restrict access to your telnet service from outside your WLAN. A stronger 

authentication mechanism, such as SSH can also be implemented.



CVE: Common Vulnerabilities and Exposures group ( reachable at 

http://cve.mitre.org/ ) was contacted and assigned CAN-2003-0512 to this 

vulnerability. 



Links:

*****

Cisco Advisory:	        http://www.cisco.com/warp/public/707/cisco-sn-

20030724-ios-enum.shtml

Vigilante Advisory: 

	http://www.vigilante.com/inetsecurity/advisories/VIGILANTE-

2003002.htm

Product Homepage: 	http://www.cisco.com/warp/public/cc/pd/witc/ps4570

CVE: CAN-2003-0512 	http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-

CAN-2003-0512





Credit:

******

This vulnerability was discovered by Reda Zitouni, member of our Security 

Watch Team at VIGILANTe. 

We wish to thank Cisco PSIRT Team for their fast answer to fix this 

problem. 

Copyright VIGILANTe.com, Inc. 2003-07-28



Disclaimer:

**********

The information within this document may change without notice. Use of 

this information constitutes acceptance for use in an AS IS condition. 

There are NO warranties with regard to this information. In no event 

shall the author be liable for any consequences whatsoever arising out of 

or in connection with the use or spread of this information. Any use of 

this information lays within the user's responsibility.



Feedback:

********

Please send suggestions, updates, and comments to 

securitywatch@vigilante.com