Cisco Security Advisory
Cisco Wireless LAN Controller and Aironet Access Points IOS WebAuth Client Authentication Bypass Vulnerability

CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N/E:X/RL:X/RC:X
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A vulnerability in Web Authentication (WebAuth) clients for the Cisco Wireless LAN Controller (WLC) and Aironet Access Points running Cisco IOS Software could allow an unauthenticated, adjacent attacker to bypass authentication and pass traffic.
The vulnerability is due to incorrect implementation of authentication for WebAuth clients in a specific configuration. An attacker could exploit this vulnerability by sending traffic to local network resources without having gone through authentication. A successful exploit could allow the attacker to bypass authentication and pass traffic.
There are no workarounds that address this vulnerability.
This advisory is available at the following link:
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180502-aironet-auth
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Vulnerable Products
At the time of publication, this vulnerability affected Cisco Aironet Access Points running Cisco IOS Software and Cisco Wireless LAN Controller (WLC) releases prior to 8.5.110.0 for the following specific WLC configuration only:
1. The Access Point (AP) is configured in FlexConnect Mode with NAT.
2. The WLAN is configured for central switching, meaning the client is being assigned a unique IP address.
3. The AP is configured with a Split Tunnel access control list (ACL) for access to local network resources, meaning the AP is doing the NAT on the connection.
4. The client is using WebAuth.
This vulnerability does not apply to .1x clients in the same configuration.
For the latest and most detailed information about affected software releases, consult the Cisco bug ID(s) at the top of this advisory.Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.
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There are no workarounds that address this vulnerability.
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For information about fixed software releases, consult the Cisco bug ID(s) at the top of this advisory.
When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories and Alerts page, to determine exposure and a complete upgrade solution.
In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.
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The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
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This vulnerability was found during the resolution of a Cisco TAC support case.
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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Version Description Section Status Date 1.0 Initial public release. - Final 2018-May-02
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