Imagine two employees at a large bank: an analyst who handles sensitive financial information and a courier who makes deliveries outside the company. As they go about their day, they look like they’re doing what they’re supposed to do. The analyst is analyzing; the delivery person is delivering. But they’re actually up to something nefarious. In the break room, the analyst quietly passes some of the secret financials to the courier, who whisks it away to a competing bank.
Now, imagine that the bank is your Android smartphone. The employees are apps, and the sensitive information is your precise GPS location.
Like the two employees, pairs of Android apps installed on the same smartphone have ways of colluding to extract information about the phone’s user, which can be difficult to detect. Security researchers don’t have much trouble figuring out if a single app is gathering sensitive data and secretly sending it off to a server somewhere. But when two apps team up, neither may show definitive signs of thievery alone. And because of an enormous number of possible app combinations, testing for app collusions is a herculean task.
A study released this week developed a new way to tackle this problem—and found more than 20,000 app pairings that leak data. Four researchers at Virginia Tech created a system that delves into the architecture of Android apps to understand how they exchange information with other apps on the same phone. Their system—DIALDroid—then couples apps to simulate how they’d interact, and whether they could potentially work together to leak sensitive information.