The researchers said they believe that the coordinates of the phone are determined by cell-tower triangulation. While the location data aren't always precise, they said the phones may have recorded up to tens of thousands of data points. However, there's no evidence that the data is being transferred beyond the devices or computers that sync with them, they said.
"The cell phone companies have always had this data, but it takes a court order to access it," the researchers wrote. "Now this information is sitting in plain view, unprotected from the world."
Aaron Higbee, chief technology officer and co-founder of mobile security firm Intrepidus Group, said that while this was the first he'd heard of the devices' tracking capabilities, his company can confirm that the files store historical location data.
"This is a good discovery," he said. "What's different in this location story is this one has a history, it's not just your point-in-time location."
Jealous Spouses, Hackers Could Exploit Data
While other rogue applications may be able to spot your location at a specific moment, this kind of tracking could be exploited by others for more nefarious reasons.
"There's a market out there for people worried about cheating spouses. I could see someone developing a app that could help open up this file and see where they've been," he said.
Cyber criminals also could create malware intended to grab a person's location history, he said.
"Things like this lead to other uses," he said. "Now, let's say you were speeding and you were required to hand over your phone to the officer? They could see where you were all day."
The location files may exist because Apple plans to roll out a future product using them or because they're an artifact of another feature on the phone, he said, but he agreed with the researchers that the discovery has privacy implications. While there isn't evidence that Apple is receiving location data now, he said, it's possible that a future operating system could retrieve it.