Cisco develops WLAN protocol to defeat password attacks

Cisco develops WLAN protocol to defeat password attacks

Cisco Systems has developed a new wireless LAN security protocol designed to defeat brute force dictionary attacks that capture a user's passwords and has submitted a draft of the protocol to the Internet Engineering Task Force (IETF).

Cisco developed the new wireless LAN Extensible Authentication Protocol-Flexible Authentication via Secure Tunnelling (EAP-FAST) to defeat dictionary attacks against unencrypted passwords in its earlier, proprietary Lightweight Extensible Authentication Protocol (LEAP). Cisco posted a security bulletin last August warning users that LEAP is vulnerable to such attacks.

Ron Seide, wireless LAN product line manager at Cisco, said EAP-FAST protects against dictionary attacks by sending password authentication between a wireless LAN client and wireless LAN access points through a secure, encrypted tunnel. Seide added that EAP-FAST also eliminates the need for enterprises to install separate servers to handle the digital certificates used in another wireless LAN security system, the Protected Extensible Authentication Protocol (PEAP).

Seide said that Cisco believes that EAP-FAST complements PEAP as well as LEAP, "bringing together some of the key advantages of LEAP's convenience and flexibility with the password protection tunnelling of PEAP".

According to Seide, Cisco submitted EAP-FAST to the IETF for inclusion in the 802.1x wireless LAN security protocol that is under development and expects to have it available for free download from its website by the end of March. Seide said Cisco does not intend EAP-FAST as a replacement for LEAP but as an addition to its wireless LAN security suite of products, which includes PEAP.

Cisco also intends to make EAP-FAST available to partners in its Cisco Compatible Extensions (CCX) program, Seide said. Cisco's CCX wireless LAN chip partners include Intel and Atheros Communications. Hardware manufacturers who are part of the CCX program include Dell, Hewlett-Packard and Toshiba.

EAP-FAST will be available to CCX partners later this year, Seide said, but he did not specify an exact date.

He said he is a "little concerned" about accommodations in the protocol to allow anonymous Diffie-Hellman exchanges that make EAP-FAST vulnerable to the same dictionary attack flaws that plague LEAP. Diffie-Hellman is an encryption scheme based on a public-key infrastructure where information transmitted between users is encrypted with a public key and decrypted with a private key.

Wright acknowledged that the draft EAP-FAST specification does not recommend the use of Diffie-Hellman in the protocol, but he said if it is used, it could negate much of the security of EAP-FAST.

Chris Kozup, an analyst at Meta Group, said EAP-FAST is a better protocol than LEAP and Cisco is opening it up to the IETF. Kozup said he expects other vendors to adopt the protocol quickly.

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