Here's how session hijacking works. The hacker waits for someone to finish successfully the authentication process. Then you as the attacker send a disassociate message, forging it to make it look like it came from the AP [access point]. The client [user] thinks they have been kicked off, but the AP thinks the client is still out there. As long as WEP is not involved you can start using that connection up until the next time out, usually about 60 minutes,

William Arbaugh