The Defcon conference is the wild and woolly version of Black Hat for the unwashed masses of hackers. It always has its share of unusual hacks. The oddest so far is a collaborative academic effort where medical device security researchers have figured out how to turn off someone’s pacemaker via remote control. They previously disclosed the paper at a conference in May. But the larger point of the vulnerability of all wirelessly-controlled medical devices remains a hot topic here at the show in Las Vegas.

Let’s not have a collective heart attack, at least not yet. The people on the right side of the security fence are the ones who have figured this out so far. But this has very serious implications for the 2.6 million people who had pacemakers installed from 1990 to 2002 (the stats available from the researchers). It also presents product liability problems for the five companies that make pace makers.

Kevin Fu, an associate professor at the University of Massachusetts at Amherst and director of the Medical Device Security Center, said that his team and researchers at the University of Washington spent two years working on the challenge. Fu presented at Black Hat while Daniel Halperin, a graduate student at the University of Washington, presented today at Defcon.

Getting access to a pacemaker wasn’t easy. Fu’s team had to analyze and understand pacemakers for which there was no available documentation. Fu asked the medical device makers, explaining his cause fully, but didn’t get any help.

William H. Maisel, a doctor at Beth Israel Deaconess Hospital and Harvard Medical School, granted Fu access for the project. Fu received an old pacemaker as the doctor installed a new one in a patient. The team had to use complicated procedures to take apart the pacemaker and reverse engineer its processes. Halperin said that the devices have a built-in test mechanism which turns out to be a bug that can be exploited by hackers. There is no cryptographic key used to secure the wireless communication between the control device and the pacemaker.

A computer acts as a control mechanism for programming the pacemaker so that it can be set to deal with a patient’s particular defribrillation needs. Pacemakers administer small shocks to the heart to restore a regular heartbeat. The devices have the ability to induce a fatal shock to a heart.

Fu and Halperin said they used a cheap $1,000 system to mimic the control mechanism. It included a software radio, GNU radio software, and other electronics. They could use that to eavesdrop on private data such as the identity of the patient, the doctor, the diagnosis, and the pacemaker instructions. They figured out how to control the pacemaker with their device.

“You can induce the test mode, drain the device battery, and turn off therapies,” Halperin said.

Translation: you can kill the patient. Fu said that he didn’t try the attack on other brands of pacemakers because he just needed to prove the academic point. Halperin said, “This is something that academics can do now. We have to do something before the ability to mount attacks becomes easier.”

The disclosure at Defcon wasn’t particularly detailed, though the paper has all of the information on the hack. The crowd here is mostly male, young, with plenty of shaved heads, tattoos and long hair. The conference is a cash-only event where no pictures are allowed without consent. It draws thousands more people from a much wider net of security researchers and hackers than the more exclusive Black Hat.

Similar wireless control mechanisms are used for administering drugs to a patient or other medical devices. Clearly, the medical device companies have to start working on more secure devices. Other hackers have figured out how to induce epileptic seizures in people sensitive to light conditions. The longer I stay at the security conferences here in Las Vegas, the scarier it gets.