[UPDATE:] Separate research has found that Android devices are caching location data in much the same way as Apple devices.
According to security researchers Pete Warden and Alasdair Allan, your iPhone or iPad is keeping a record of every step you take, storing this data and sharing it with the devices that sync with the iPhone or iPad. What's troubling is that this information is unencrypted and can be accessed and viewed by anyone.
According to The Guardian, Warden and Allan discovered that devices running iOS 4 keep a record of time-stamped coordinates in a file called "consolidated.db."
When the iPhone or iPad is connected to a laptop, this sensitive file is copied from the portable device to the laptop. Anyone who opens the file can scroll through and see a history of where you've been.
The pair have set up a site explaining their discovery. From their description:
Cell-phone providers collect similar data almost inevitably as part of their operations, but it's kept behind their firewall. It normally requires a court order to gain access to it, whereas this is available to anyone who can get their hands on your phone or computer. [...] By passively logging your location without your permission, Apple have made it possible for anyone from a jealous spouse to a private investigator to get a detailed picture of your movements.
Why are these Apple devices storing users' geolocation data? The answers are not immediately apparent.
"One guess might be that they have new features in mind that require a history of your location, but that's pure speculation. The fact that it's transferred across devices when you restore or migrate is evidence the data-gathering isn't accidental," Warden and Allen say on their site.
They also believe that Apple may be the only company whose devices are storing customers' geolocation data.
"Alasdair has looked for similar tracking code in [Google's] Android phones and couldn't find any," Warden told The Guardian. "We haven't come across any instances of other phone manufacturers doing this."
Warden and Allen have developed an iPhone Tracker app that maps the location data stored in the iDevice. You can watch a video (below) to see a visualization of an iPhone owner's trip from Washington D.C. to New York City and back.
For more about how this data is collected, how accurate it is and what you can do to protect it, click here.