Well, thanks to a new Firefox extension called Firesheep, anyone can easily view other people on their network and, with a click of a button, assume another person's identity and login credentials from any non-secure site that the unwitting person is logged into.
Firesheep was created by two developers who are hoping to shine a light on the problem of websites that don't use SSL encryption throughout an entire user session. It has always been easy for the bad guys to view and steal login information from users accessing non HTTPS-secured websites and Firesheep is just making that a whole lot easier.
To a certain degree this is a worthwhile cause. Too many sites put users at risk of giving away their login information by their failure to use secure connections. However, I wish the Firesheep developers could have made their point without putting this tool in the hands of bad guys, cranky teens, and disgruntled employees everywhere.
And don't think that because a webmail site or ecommerce site uses SSL for the login page that you're safe. If SSL isn't enabled for the entire session, someone using Firesheep can still take over your account after you've logged in.
Also, this problem isn't limited to Wi-Fi hotspots. Someone using Firesheep can see and steal the login information from anyone on a shared network segment, whether that's a hotspot, a home network, or a company network.
So what can you do to avoid the dangers of Firesheep (and the older sniffing tools familiar to real hackers)?
For those traveling or using public networks and hotspots, a VPN is probably your best option, as it will encrypt your entire Internet connection. But not everyone has access to a VPN, especially when it comes to non-business users.
The second best option is to make sure that the site you are using has https enabled throughout the entire session. Some sites, like Google Gmail, now do this by default, but that isn't the case for every site.
However, not every site has the capability to run under HTTPS for an entire session. Some sites use it only for login (which doesn't protect you against Firesheep) and some don't use it at all.
In these cases, if you don't have a VPN handy, then I would advise not using these sites or services at all when you are on a network that you don't trust 100%.
Of course the best solution would be for all sites that need to protect user information, whether they are webmail, social networks, or ecommerce sites, to use HTTPS all the time.
And with the threat of Firesheep out there, they all might finally do that.