After infiltrating one of the biggest and most abusive known botnets, security researchers are wrestling with a thorny ethical dilemma: should they exorcise tens of thousands of possessed machines or simply leave them be?

Pedram Amini and Cody Pierce, of security provider TippingPoint, reverse engineered the executable behind the notorious Kraken botnet, a feat that allowed them to build a fake server that receives connections from zombie machines looking for instructions about who and what to spam. Over the course of a week, an estimated 25,000 machines, most belonging to home broadband users, reported for duty. That's as much as 14 percent of the entire Kraken population, according to some estimates.

"This is where we entered into a moral dilemma and ethical discussion," Amini wrote in an entry on the TippingPoint DVLabs blog. "We have the ability to successfully redirect infected systems. We have the ability to provide an 'update' through the existing Kraken protocol that can simply remove the Kraken zombie. Is it wrong to do so?"

For the moment, there appears to be an internal difference of opinion at TippingPoint. Amini and Pierce are both in favor of removing the bots, a move that in a single keystroke would likely make the machines run better and, more importantly, would rid the internet of 25,000 spam-barfing machines.

But TippingPoint boss Dave Endler sees things differently. What if the deed has the unintended consequence of bringing down a machine, and what if said machine is responsible for someone's life support? The hypothetical is a bit extreme (is anyone foolhardy enough to rely on a Windows PC for life support?), but it still captures the essence of why intervention may not be a good idea. No matter how good their intention, the researchers could find themselves in trouble should anything go wrong.

So for the time being, the company, which provides intrusion prevention products for large companies, will simply allow these demonic machines to go about their business. That's a shame, because as we reported earlier, the Kraken architects have gone to great lengths to cloak infected machines and make them hard to disinfect. Now that they've learned that their brainchild has been reverse engineered, who knows when such a chance will come around again? ®