It didn't take much to hack into the heart monitoring device and get it to administer a 137-volt shock: an oscilloscope, a PC, a wireless radio with a couple of antennas and some free software.
With those tools, a group of university researchers were able to gain access to what is known as an implantable cardioverter defibrillator (ICD), reading sensitive patient information, disrupting its operation and even programming it to repeatedly administer strong electric shocks.
These tiny life-saving ICD devices are surgically implanted in the chests of heart patients, wired to the heart so they can shock it out of ventrical fibrillation. This is a heart-attack condition in which the heart muscle twitches randomly instead of pumping blood in a coordinated fashion.
They've been used in the US since 2003, but until now have never been subject to a rigorous public security review, according to Tadayoshi Kohno, an assistant professor with the University of Washington, who co-authored a paper looking into the security of ICDs and pacemakers.
"We conducted some experiments that show that although there is a very remote risk of someone tampering [with] or accessing someone's implantable device, there is a risk," he said.
Part of the problem is that some pacemakers and ICD devices, including the Medtronic Maximo studied by the researchers, are designed to be remotely controlled over an unencrypted wireless protocol. That means that, given a "fair bit of time" to figure out the wireless protocol, a technically savvy hacker can start reading data and controlling the defibrillator.
The kind of shock that these devices can deliver at their most powerful settings can be intense, feeling like a kick to the chest.
The research shows that medical regulators now need to think about new issues as computerised and networked equipment is being implanted into humans, said Gadi Evron, a networking security expert based in Israel. "What I would like to see are security standards being put into place alongside with the regulations," he said.
Device manufacturers need to think more about security, said Evron, who discussed the idea of viruses in human implants at the Chaos Computer Camp hacking conference last year.
Although the results of this week's study may seem scary at first glance, Kohno says the odds of someone actually carrying out this attack are low, because the hacker would have to somehow get all of this equipment within 4 inches (10 centimeters) of a target ICD.
And while Kohno is by no means advising heart patients to stay away from these life-saving devices, he believes that the research should help the medical industry take security more seriously as it develops the next generation of these products, some of which may have a much greater wireless range. "Future devices need to incorporate a strong security mechanism," he said.
Kohno has already seen first-hand what happens when insecure technology becomes widely adopted. He was one of the authors of an influential 2003 paper on the security of electronic voting machines that helped push many states to re-evaluate their use of these devices.
"One of the lessons… we learned from electronic voting, [is] it's important to understand the risks of new technologies before they're widely deployed," Kohno said. "I really wish that someone had done a similar type of public analysis five or 10 years before we did the analysis that we did."
Published on earlier this week, the paper was written by researchers at the University of Washington, the University of Massachusetts, Amherst, and Harvard Medical School. They will publicly present their findings in May at a security symposium in Oakland, California.