Beware! Now even any Jack can hijack your session with a new Firefox plugin tool- Firesheep . All what he needs to do is to just install this tool in Firefox and start sniffing the communications on a public unencrypted Wi-Fi. Public Wi-Fi systems are generally unencrypted at Airports, Cafes etc. Some web sites like Facebook serves the login page on https but all the internal pages at http, once authenticated. That makes this kind of websites more prone to sniffing, and an unencrypted Wi-Fi adds more problems. After authentication this kind of websites generally assigns some session identifiers to the user which can be easily sniffed and can be used to impersonate. Surely, it's not a new concept, but what makes Firesheep more dangerous is that it's just a click-and-hijack tool that a novice user can also use at the public places to sniff other's credentials. The author's of this tool wanted to draw attention of people on those kind of websites which don't implement ...