Cisco Aironet Access Points Ethernet Wired Clients Denial of Service Vulnerability

Vulnerability

A vulnerability in the Ethernet packet handling of Cisco Aironet Access Points (APs) Software (CVE-2020-3552) allows an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition. The issue stems from insufficient input validation in the software. Affected versions include multiple Cisco Aironet AP models running vulnerable firmware versions prior to the fixed releases indicated in Cisco Security Advisory cisco-sa-ap-ethport-dos-xtjTt8pY [1].

Exploitation

An attacker can exploit this vulnerability by physically or logically connecting as a wired client to the Ethernet interface of an affected device. The attacker then sends a series of specific packets within a short time frame. No authentication is required; the attacker only needs adjacent network access to the wired port [1].

Impact

A successful exploit triggers a NULL pointer access, causing the affected device to reload. This results in a temporary denial of service (DoS) condition, interrupting wireless and wired network services provided by the access point [1].

Mitigation

Cisco has released free software updates to address the vulnerability. Customers are advised to upgrade to the fixed software versions listed in the advisory. No workaround is available. For customers without service contracts, contacting Cisco TAC is recommended to obtain the upgrade [1].