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