A vulnerability in the 802.11r Fast Transition (FT) implementation for Cisco IOS Access Points (APs) Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected interface. The vulnerability is due to a lack of complete error handling condition for client authentication requests sent to a targeted interface configured for FT. An attacker could exploit this vulnerability by sending crafted authentication request traffic to the targeted interface, causing the device to restart unexpectedly. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190717-aironet-dos
A vulnerability in the 802.11r Fast Transition (FT) implementation for Cisco IOS Access Points (APs) Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected interface.
The vulnerability is due to a lack of complete error handling condition for client authentication requests sent to a targeted interface configured for FT. An attacker could exploit this vulnerability by sending crafted authentication request traffic to the targeted interface, causing the device to restart unexpectedly.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190717-aironet-dos
This vulnerability affects Cisco Access Points that are running an affected version of Cisco IOS Access Point Software configured for 802.11r FT.
Verification of 802.11r Fast Transition (FT) Configuration From the CLI:
Procedure:
From the CLI of the WLC for which the AP is associated, administrators may issue the following show command to verify if the 802.11r FT feature is configured on the device.
Command:
(Cisco Controller) > show wlan <wlan id>Security802.11 Authentication................Open SystemFT Support.....................DisabledStatic WEP Keys................Disabled802.1X.........................DisabledWi-Fi Protected Access (WPA/WPA2).....Enabled
Verifying 802.11r Fast Transition (FT) Configuration From the (GUI):
Procedure:
Step 1: Choose the WLANs tab to open the WLANs window.
Step 2: Click a WLAN ID.
Step 3: Choose Security > Layer 2 to verify if the Fast Transition feature is enabled or disabled on the device.
It is important to note the available adaptive option that exists within the drop-down menu when configuring 802.11r Fast Transition for the respective WLAN. This feature, if selected, could allow compatible 802.11r Fast Transition wireless clients to utilize Fast Transition and become vulnerable to the issue listed in the Summary section.
For information about which Cisco Access Point Software releases are vulnerable, see the Fixed Software section of this advisory.
No other Cisco products are known to be affected by this vulnerability.
Cisco has released free software updates that address the vulnerability described in this advisory. Customers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license:
https://www.cisco.com/c/en/us/products/end-user-license-agreement.html
Additionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades.
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.
Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC:
https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html
Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.
In the following table, the left column lists major Cisco software releases. The right column indicates whether a major release is affected by the vulnerability described in this advisory and the first minor release that includes the fix for this vulnerability.
| Cisco IOS Access Points Major Software Release | First Fixed Release for This Vulnerability |
| Prior to 8.0 | 8.2.170.0 |
| 8.0 | 8.2.170.0 |
| 8.1 | 8.2.170.0 |
| 8.2 | 8.2.170.0 |
| 8.3 | 8.3.150.0 |
| 8.4 | 8.5.131.0 |
| 8.5 | 8.5.131.0 |
| 8.6 | 8.8.100.0 |
| 8.7 | 8.8.100.0 |
| 8.8 | Not vulnerable |
| 8.9 | Not vulnerable |
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.
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.
| Version | Description | Section | Status | Date |
|---|---|---|---|---|
| 1.0 | Initial public release. | - | Final | 2019-July-17 |
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