On today's program, we reported on a new plug-in called Blacksheep that's designed to thwart anyone using the Firesheep spy plug-in.

Essentially, it serves up fake web cookies to Firesheep, Firesheep takes them, and the cookies announce Firesheep's presence on the network to anyone who has the Blacksheep add-on.

Sheep fight!

Now, Eric Butler, who created Firesheep, he says as a way of demonstrating the lack of security on open networks, says that's no solution. An attacker can use a VPN to hide themselves or use another tool similar to Firesheep.

Butler responded to the ethical and legal questions about his software with a blog post here .