Firesheep: Firefox allows simple HTTP session hijacking

Eric Butler, a separate Web application and software developer, has launched a new extension for Firefox called Firesheep weekend which aims to highlight the lack of security around user logins and cookies from sites popular Web sites such as Facebook.

Firesheep be added to any other add-ons. Once installed, it displays a sidebar that displays new information about individual users registered on sites like Facebook when connecting through an unsecured network and open. If a user appears in the sidebar Firesheep can log in as a double click of your mouse. Simple as that.
Firesheep work because of lack of security at the site. If a user name and password can be protected by SSL encryption, the site uses a cookie is in many cases once the entry has been a success. So once a user has connected is a simple removal of the cookie without taking into account the protection of this session.