Headline
CVE-2023-20100: Cisco Security Advisory: Cisco IOS XE Software for Wireless LAN Controllers CAPWAP Join Denial of Service Vulnerability
A vulnerability in the access point (AP) joining process of the Control and Provisioning of Wireless Access Points (CAPWAP) protocol of Cisco IOS XE Software for Wireless LAN Controllers (WLCs) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to a logic error that occurs when certain conditions are met during the AP joining process. An attacker could exploit this vulnerability by adding an AP that is under their control to the network. The attacker then must ensure that the AP successfully joins an affected wireless controller under certain conditions. Additionally, the attacker would need the ability to restart a valid AP that was previously connected to the controller. A successful exploit could allow the attacker to cause the affected device to restart unexpectedly, resulting in a DoS condition.
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.
Cisco IOS and IOS XE Software
To help customers determine their exposure to vulnerabilities in Cisco IOS and IOS XE Software, Cisco provides the Cisco Software Checker. This tool identifies any Cisco security advisories that impact a specific software release and the earliest release that fixes the vulnerabilities that are described in each advisory (“First Fixed”). If applicable, the tool also returns the earliest release that fixes all the vulnerabilities that are described in all the advisories that the Software Checker identifies (“Combined First Fixed”).
To use the tool, go to the Cisco Software Checker page and follow the instructions. Alternatively, use the following form to determine whether a release is affected by any Cisco Security Advisory. To use the form, follow these steps:
- Choose which advisories the tool will search-only this advisory, only advisories with a Critical or High Security Impact Rating (SIR), or all advisories.
- Enter a release number-for example, 15.9(3)M2 or 17.3.3.
- Click Check.