The desktop Web browser has long been a security sinkhole. It's grown deeper, despite emphasis on secure coding, greater user awareness, improvements to Internet Explorer and the use of alternatives like Firefox and Opera. Criminals lure users to thousands of malicious or compromised Web sites to scam their identity information or drop some nasty code on their computers.

Detecting these sites and collecting and countering exploits has been somewhat like playing Whack-A-Mole, but security researchers are finding effective ways to fight back. Microsoft and open source advocates are pursuing two of the more promising initiatives, aggressively hunting for exploits using honeyclients, an active variation of honeynet techniques.

While honeynets have been around for some time, they are passive collectors, sitting on some random network on the Internet, waiting for a hacker to connect to and leave evidence. Typically, they consist of a Web server and a stripped-down operating system with tracking software that registers when a hacker tries to compromise the system. While they are great at documenting exploits, they have one big disadvantage: They can't go out and actively search for the bad guys who are running Web sites designed to infect unsuspecting visitors.

Honeyclients, however, are hunters, not decoy victims; they run Web browsers and actively seek dangerous sites.