A vulnerability in the Cisco Aironet 1560, 1800, 2800, and 3800 Series Access Points (APs) software could allow an authenticated, adjacent attacker to cause an affected device to reload unexpectedly, resulting in a denial of service (DoS) condition.
The vulnerability is due to a deadlock condition that may occur when an affected AP attempts to dequeue aggregated traffic that is destined to an attacker-controlled wireless client. An attacker who can successfully transition between multiple Service Set Identifiers (SSIDs) hosted on the same AP while replicating the required traffic patterns could trigger the deadlock condition. A watchdog timer that detects the condition will trigger a reload of the device, resulting in a DoS condition while the device restarts.
Cisco has released software updates that address this vulnerability.
This advisory is available at the following link:
This vulnerability affects only Cisco 1560, 1800, 2800, and 3800 Series Access Points that are running a vulnerable release of Cisco Mobility Express (ME) Software. For information about affected software releases, consult the Cisco bug ID(s) at the top of this advisory.
Determining the Cisco Mobility Express Software Release
To determine which Cisco Mobility Express Software release is running on a device, administrators can use the web interface or the CLI of the device.
To use the web interface, do the following:
og in to the web interface
- Choose System Software > Software Upgrade
- Refer to the value in the System Software Version field
To use the CLI, log in to the AP through a Telnet or an SSH session, issue the show version command, and then refer to the command output. The following example shows the command output for a Cisco Aironet 1852i Access Point that is running Cisco Mobility Express Software Release 18.104.22.168:
AP# show version cisco AIR-AP1852I-UXK9 ARMv7 Processor rev 0 (v71) with 997184/525160K bytes of memory. Processor board ID RFDP2BCR021 AP Running Image : 22.214.171.124 Primary Boot Image : 126.96.36.199 Backup Boot Image : 188.8.131.52 AP Image type : MOBILITY EXPRESS IMAGE AP Configuration : MOBILITY EXPRESS CAPABLE . . .
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.
Cisco has confirmed that this vulnerability does not affect the following Cisco products:
- Small Business 100 Series Access Points
- Small Business 300 Series Access Points
- Small Business 500 Series Access Points
- Aironet 1540 Series Access Points
Note: The Cisco Aironet 1550 Series Outdoor Access Point was not investigated because it has entered the end-of-life process. Refer to the End-of-Sale and End-of-Life Announcement for the Cisco Aironet 1550 Series Outdoor Access Point for additional information.
There are no workarounds that address this vulnerability.
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.
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 during resolution of a TAC support case.
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 2018-October-17
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.