A vulnerability in Cisco Aironet Access Points (APs) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) on an affected device.
The vulnerability is due to improper resource management while processing specific packets. An attacker could exploit this vulnerability by sending a series of crafted UDP packets to a specific port on an affected device. A successful exploit could either allow the attacker to tear down the connection between the AP and the wireless LAN controller, resulting in the affected device not being able to process client traffic, or cause the vulnerable device to reload, triggering a DoS condition. After the attack, the affected device should automatically recover its normal functions without manual intervention.
Cisco has released software updates that address the vulnerability described in this advisory. There are no workarounds that address this vulnerability.
This advisory is available at the following link:
This vulnerability affects the following Cisco products if they are running a vulnerable software release:
- Aironet 1540 Series APs
- Aironet 1560 Series APs
- Aironet 1800 Series APs
- Aironet 2800 Series APs
- Aironet 3800 Series APs
- Aironet 4800 APs
- Business 100 Series APs and Mesh Extenders
- Business 200 Series APs
- Catalyst 9100 APs
- Catalyst IW 6300 APs
- ESW6300 Series APs
- Integrated Access Point on 1100 Integrated Services Routers
Note: For Cisco Catalyst 9100 APs, Release 126.96.36.199 is the first supported release.
For information about which software releases are vulnerable, see the Fixed Software section 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.
The vulnerability described in this advisory presents two different nuances. The exploit techniques and attack vectors are almost identical, and the fixed code addresses both of them. In this section, administrators can find additional details about these two security issues:
- CSCvr85614 can be exploited by an attacker connected over the network, targeting any AP regardless of its deployment mode. Exploiting this vulnerability would cause the targeted AP to lose the connection to its controller, which could lead to client network loss or radio resets, depending on the configuration. The AP should recover on its own when the attack stops.
- CSCvr85609 can also be exploited by an attacker connected over the network and is also independent of the AP deployment mode. Exploiting this vulnerability would cause the AP to unexpectedly reload. The device should recover automatically after a few minutes without manual intervention.
There are no workarounds that address 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 Without Service Contracts
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.
The process to upgrade the APs requires administrators to upgrade the wireless controller that the APs are registered to.
In the following table(s), the left column lists Cisco Wireless Controller software releases. The center column indicates whether a release is affected by the vulnerability described in this advisory and the first release that includes the fix for this vulnerability. The right column indicates whether a release is affected by all the vulnerabilities described in this collection of advisories and which release includes fixes for those vulnerabilities. To ensure a complete upgrade solution, consider that this advisory is part of a collection that includes the following advisory:
- cisco-sa-ap-ethport-dos-xtjTt8pY: Cisco Aironet Access Points Ethernet Wired Clients Denial of Service Vulnerability
Cisco Access Points Managed by Cisco Wireless LAN Controller
Cisco Wireless LAN Controller Software Major Release First Fixed Release for This Vulnerability First Fixed Release for All Vulnerabilities Described in This Collection of Advisories 8.5 and earlier 188.8.131.52 184.108.40.206 8.6 220.127.116.11 18.104.22.168 8.7 22.214.171.124 126.96.36.199 8.8 188.8.131.52 184.108.40.206 8.9 220.127.116.11 18.104.22.168 8.10 22.214.171.124 126.96.36.199
Cisco Access Points Managed by Cisco Catalyst 9800 Wireless Controller
Cisco Catalyst 9800 Wireless Controller Software Major Release First Fixed Release for This Vulnerability First Fixed Release for All Vulnerabilities Described in This Collection of Advisories 16.12 and earlier 16.12.4a 16.12.4a 17 Not vulnerable. Not vulnerable.
Cisco Business Access Points Software
Cisco Business AP Software Major Release First Fixed Release for This Vulnerability First Fixed Release for All Vulnerabilities Described in This Collection of Advisories 10.0 10.1.1.0 10.1.1.0
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.
This vulnerability was found by Dakshil Shah and Shu Xiao of Cisco during internal security testing.
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 2020-SEP-24
THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.
A standalone copy or paraphrase of the text of this document that omits the distribution URL is an uncontrolled copy and may lack important information or contain factual errors. The information in this document is intended for end users of Cisco products.