Homeland Security has issued a warning for a set of critical-rated vulnerabilities in Medtronic defibrillators which put the devices at risk of manipulation. These small implantable cardio-defibrillators are implanted in a patient’s chest to deliver small electrical shocks to prevent irregular or dangerously fast heartbeats, which can prove fatal. Most modern devices come with wireless or radio-based technology to allow patients to monitor their conditions and their doctors to adjust settings without having to carry out an invasive surgery. But the government-issued alert warned that Medtronic’s proprietary radio communications protocol, known as Conexus, wasn’t encrypted and did not require authentication, allowing a nearby attacker with radio-intercepting hardware to modify data on an affected defibrillator. Homeland Security gave the alert a 9.3 out of 10 rating, describing it as requiring “low skill level” to exploit. It doesn’t mean that anyone with an affected defibrillator is suddenly a walking target for hackers.