The iPhone tracking story, one week later

Apple issues a statement on location and says iOS fixes are coming soon.

By Alasdair Allan and Pete Warden

It’s now been a week since we published the iPhone tracking story, so it seemed a good time to cover what we’ve learned.

The fix

iPhone trackApple has just released a Q&A covering this problem and they will be fixing the issues we spotted with a software update. “The reason the iPhone stores so much data is a bug we uncovered,” Apple notes in the statement.

Apple explains that nearby locations are pulled down from an Apple database and stored on the phone. These locations are from a “crowd-sourced database of Wi-Fi hotspot and cell tower data.” This matches the picture that was emerging from research. It explains why there’s lots of locations that don’t match towers, and also why the accuracy is within a few-hundred meters, since we’ve learned that “micro-cells” in urban areas are clustered closely together.

The Q&A explains the technical workings behind the log and reassures us that only anonymous data is sent back. Our conclusions still apply.

Apple doesn’t address our claim that this reveals sensitive information about your travels. At this point we’re just relieved to get an explanation and a fix, but people can examine their own data and decide for themselves how happy they would be sharing it with strangers.


What Does Your iPhone Know About You? More Than You Think — Alexis Madrigal has written a fascinating follow-up piece covering the data that professionals can read from your phone. Using forensics tools like the Lantern program that Alex Levinson helped build, anyone with physical access to the device can construct a picture of the user’s life. It’s eye-opening what the “law enforcement, government, and corporate examiners” who purchase the system can uncover about your behavior.

The Tell-all telephone visualization also makes for thoughtful viewing. It’s built from details that a German politician forced his cell phone provider to share after it was caught storing six months of location data on its subscribers. I think one of the reasons that the iPhone Tracker application has had so much use is that it shows people their own data in an understandable way. Unfortunately, that means that similar information that’s harder to access behind a company’s firewall may not get the same scrutiny, just because it’s harder to show in a way that connects with people.

Uses for good

I’ve long been a fan of Geoloqi’s opt-in service for recording and sharing your travels, but several other projects in the same area have appeared in my inbox over the last few days. Maria Scileppi has created the Living Brushstroke project (see video below) to capture people’s movements at events, and turn the data into art. Intriguing and beautiful patterns emerge as people cross paths. It’s a very fresh way to look at our lives.


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  • David

    Don’t you think that Google was unfairly dragged into this debate? seeing as Apple’s upcoming update would bring the iPhone on par with Android in this regard (more user control and limited local cache).

  • Alistair

    I am perfectly happy sharing sensitive information about my travels to Sanquhar, Kinross, New Cumnock, etc. Mostly because I’ve never actually been there, although my consolidated.db file has records for those locations.

    The mature thing would have been to admit that your “Apple is recording your moves” article was a bit inaccurate. Pretending that Apple just confirmed everything you originally claimed is not.

  • Skippy

    I agree RADAR needs to publish a apology to Apple and a retraction about their wild reporting without any proper research that used link bating , lies , hype , innuendo and scare tactics and as it turned out no facts and they still wont credit others for work done previously…

    It actually wasn’t tracking users as RADAR made out it was plotting wifi cell tower locations in the area that the other credible researchers had already known or found out about… any one with common sense realized this..

    And this article is just a fluff piece with no apology and only highlight stuff we found out once getting through all their hype ..

  • ath0


    Not at all, I’m extremely interested in why Google’s phones are transmitting the location so often (several times per hour according to reports)

    Also I’m very interested in why Android sends the unique device ID and the carrier user ID to AdMob servers for AdMob-supported apps (and there’s so many of them).

    Let’s hear what they have to say about that.

    (see ArsTechnica article if you don’t believe me)

    But of course Google is O’Reilly’s friend and parter so we’ll never see it properly mentioned here.

  • Paul

    I think it’s a shame that you guys didn’t think about whether the data you found was a log or cache. Clearly the reason that the return trip from New York to Washington (featured in your 20 minute video) didn’t have as many points compared to the outward trip was that the cell towers along that route had already been cached and didn’t need to be fetched again.

    Did you not notice that each cell tower/wi-fi hotspot is only mentioned once in the database file? If Apple was really “tracking” your movements over time, the locations you went to repeatedly would be in the database several times.

    And as others have pointed out, a quick review of the WWDC session from last year about Core Location would not have hurt either. It explains how iOS preemptively fetches cell tower and wi-fi location data from Apple for a radius around your current location. You know, like a cache?

  • David


    It’s the same triangulation data, it doesn’t matter how often it’s being sent – except it helps with the compilation of a more accurate dataset – and they provide notice and control for that as well.

    As for the the device ID they recently added that to target ads better, they are running admob ads to inform about the change and the ad targeting is now controllable via the market.

    There is nothing nefarious about any of this.

  • ath0


    So let me get this right:

    1) Google sends your location data every two hours (or even more frequently) back to them, apparently anonymized but the data is coming from your IP address.

    2) Google sends your unique Device ID and most likely using the same IP address (it doesn’t change THAT often) to target ads.

    Can you see how we have to trust Google not to combine both pieces of data and figure out where you are at almost any time of day? Problem is combining data and selling it is Google’s core business.

    As for informing people, well they don’t inform about how this combination opens up such a breach.

    I think this is quite a bit worse than Apple. But hey if not let’s hear Google’s side of it.

  • Chris

    @Paul, you’d think that finding the consolidated.db file in a subdirectory called “Caches” may have tipped them off. But apparently it didn’t.

    Also, if one were looking at a tracking log, one would expect monotonically-increasing timestamps of locations that may repeat as the user either didn’t move or returned to the same location. But what the databases show is that the same location is never repeated, and that many disparate locations have the identical timestamp. The authors’ “heatmap” visualization obscures both of these anomalies, but a screenshot of it looks an awful lot like a tracking log—except for the fact that it doesn’t reflect the reality of the places the phone actually was chronologically.

    I’m astonished that the authors still “stand by their conclusions” after being so clearly wrong about the nature of the data and wrongly playing up the mystery of it.

  • Doug

    The real damage here is that the original report by Pete and Alasdair gave everyone the impression that the iPhone was keeping a log of your location over time, which is simply not true. It’s cache, as other people have said, with at most one entry per location.

    Almost every report I’ve seen about this in both tech and mainstream media immediately jumped on this, and so it was widely reported that iPhones keep a log of your movements. The implication was you could enter a date and time and the log would tell show where you were at the time. Again this is not the case.

    If only Pete and Alasdair had been a bit more careful with their investigation, and then explained what it was they had found with more care, then the whole thing wouldn’t have been blown out of proportion.

  • Doug

    Here’s a an example from today:

    “A pair of researchers discovered last month that Apple’s iPhone stores information on every move its user makes for up to a year, and it’s not encrypted, so anyone who gets a hold of your phone can see where you’ve been.”

    The basic incorrect story that Pete and Alasdair spread has become an established fact that keeps being repeated by the media. They should have made it clear that the iPhone doesn’t track every move it makes.