(CNN) -- Apple devices appear to be tracking their owners' locations and storing data about people's whereabouts without their knowledge, according to a report posted Wednesday on a site called iPhone Tracker.
The unauthorized surveillance started in June 2010, when the latest version of Apple's mobile operating system was released, according to two researchers who say they discovered a hidden tracking file and posted it out of concern for users.
Apple has not responded to the allegations.
The researchers have posted a program online that will let any iPhone user see a map of his or her location over time, going back to June, when iOS 4.0 was released.
The program's developers, listed as Alasdair Allan and Pete Warden, say this data is stored on a person's iPhone or 3G-enabled iPad and on computers that are synced with those devices. There's no evidence, they say, that the data is also transmitted to Apple as it's collected.
"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," they write.
"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."
The location data appear to be collected at random intervals over time, using cell phone towers to triangulate approximate locations, they write.
They say these data are stored in a file named "consolidated.db," and that it's "unclear" why Apple would collect this information.
"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," they write on the iPhone Tracker site.
Some iPhone users expressed outrage at the news.
Sam Biddle, an editor at Gizmodo, used the downloadable program to map out his recent whereabouts, which he says was a frightening experience.
"This is a map of everywhere I've been for the last months. Everywhere," he writes on that tech site. "I didn't carry around a tracking device. The FBI isn't sending goons in unmarked vans to track me. All I did was use an iPhone."
He adds: "The data itself is jarringly accurate. Even though it appears to rely on tower triangulation rather than GPS pinpointing (meaning you're not safe with location services switched off), the map I was able to generate with mapping software the security duo released visualizes my life since the day I bought my iPhone 4 in July. Everywhere I've been. Bus trips home. Train trips to visit family. Vacations. Places I'd forgotten I'd even gone. Zoom in on that giant blotch over New York, and you can see my travels, block by block.
"My entire personal and professional life -- documented by a phone I didn't know was also a tracking device. It's all accessible -- where I've been, and when. I don't really have anything to hide, which is why I don't mind sharing the map. But it's just not right to have no choice in the matter; I don't want this information bouncing around in my pocket with me."
Others, including Forbes writer Kashmir Hill, wonder if this feature is "cool or creepy." She decides on "cool," writing that the program is "like a persistent, pervasive, secret location-diary."