Headline
CVE-2021-1437: Cisco Security Advisory: Cisco Aironet Access Points FlexConnect Upgrade Information Disclosure Vulnerability
A vulnerability in the FlexConnect Upgrade feature of Cisco Aironet Series Access Points Software could allow an unauthenticated, remote attacker to obtain confidential information from an affected device. This vulnerability is due to an unrestricted Trivial File Transfer Protocol (TFTP) configuration. An attacker could exploit this vulnerability by sending a specific TFTP request to an affected device. A successful exploit could allow the attacker to download any file from the filesystem of the affected access point (AP).
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.htmlAdditionally, 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 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.
Fixed Releases
The process to upgrade the APs requires administrators to upgrade the wireless controller that the APs are registered to.
Customers are advised to upgrade to an appropriate fixed software release as indicated in the following table(s). To ensure a complete upgrade solution, consider that this advisory is part of a collection that includes the following advisories:
- cisco-sa-aironet-info-disc-BfWqghj: Cisco Aironet Access Points FlexConnect Upgrade Information Disclosure Vulnerability
- cisco-sa-aironet-mdns-dos-E6KwYuMx: Cisco Aironet Access Points FlexConnect Multicast DNS Denial of Service Vulnerability
- cisco-sa-ap-privesc-wEVfp8Ud: Cisco Access Point Software Arbitrary Code Execution Vulnerability
Cisco Access Points Managed by Wireless LAN Controller or Mobility Express
Cisco Wireless LAN Controller Software Release
First Fixed Release for This Vulnerability
First Fixed Release for All Vulnerabilities Described in This Collection of Advisories
Earlier than 8.10.112.0
Not vulnerable.
8.10.151.0
8.10.112.0 and later
8.10.142.0
8.10.151.0
Cisco Access Points Managed by Catalyst 9800 Wireless Controller or Embedded Wireless Controller on Catalyst Access Points (EWC)
Cisco Catalyst 9800 Wireless Controller Software Release
First Fixed Release for This Vulnerability
First Fixed Release for All Vulnerabilities Described in This Collection of Advisories
Earlier than 17.1
Not vulnerable.
17.3.3
17.1
Migrate to a fixed release.
17.3.3
17.2
Migrate to a fixed release.
17.3.3
17.3
Migrate to a fixed release.
17.3.3
17.4 and later
Not vulnerable.
17.5.1 (Mar 2021)