To defeat a malicious botnet, build a friendly one

Beating the "botnets"–armies of infected computers used to attack websites–requires borrowing tactics from the bad guys, say computer security researchers.

A team at the University of Washington, US, wants to marshal swarms of good computers to neutralize the bad ones. They say their plan would be cheap to implement and could cope with botnets of any size.

Their system, called Phalanx, uses its own large network of computers to shield the protected server. Instead of the server being accessed directly, all information must pass through the swarm of "mailbox" computers.

https://technology.newscientist.com/article/dn13753-to-defeat-a-malicious-botnet-build-a-friendly-one.html

Urs