Lightweight Extensible Authentication Protocol

The Lightweight Extensible Authentication Protocol (LEAP) is a proprietary wireless LAN authentication method developed by Cisco Systems. Important features of LEAP are dynamic WEP keys and mutual authentication (between a wireless client and a RADIUS server). LEAP allows for clients to reauthenticate frequently; upon each successful authentication, the clients acquire a new WEP key (with the hope that the WEP keys don't live long enough to be cracked).

Some 3rd party vendors also support LEAP through the Cisco Compatible Extensions Program, as listed here: http://www.cisco.com/web/partners/pr46/pr147/partners_pgm_concept_home.html

Security Considerations

LEAP uses a modified version of MS-CHAP, an authentication protocol in which user credentials are not strongly protected. Stronger authentication protocols employ a salt (cryptography) to strengthen the credentials against eavesdropping during the authentication process. Cisco's response to the weaknesses of LEAP suggests that network administrators either force users to have stronger, more complicated passwords or move to another authentication protocol also developed by Cisco, EAP-FAST, to ensure security. Automated tools like ASLEAP demonstronstrate the simplicity of getting unauthorized access in networks protected by LEAP implementations.