Cryptographic flaw in Cisco Small Business 100 Series Wireless Access Points

Summary

A vulnerability in the implementation of Extensible Authentication Protocol over LAN (EAPOL) functionality in Cisco Small Business 100 Series Wireless Access Points and Cisco Small Business 300 Series Wireless Access Points could allow an unauthenticated, adjacent attacker to force the downgrade of the encryption algorithm that is used between an authenticator (access point) and a supplicant (Wi-Fi client). The vulnerability is due to the improper processing of certain EAPOL messages that are received during the Wi-Fi handshake process. An attacker could exploit this vulnerability by establishing a man-in-the-middle position between a supplicant and an authenticator and manipulating an EAPOL message exchange to force usage of a WPA-TKIP cipher instead of the more secure AES-CCMP cipher. A successful exploit could allow the attacker to conduct subsequent cryptographic attacks, which could lead to the disclosure of confidential information. Cisco Bug IDs: CSCvj29229.