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Cellphones Data Storage Privacy Security

Wiping a Smartphone Still Leaves Data Behind 155

Posted by Soulskill
from the why-you-always-smash-them-with-a-hammer-before-reselling-them dept.
KindMind writes "To probably no one's surprise, wiping a smartphone by standard methods doesn't get all the data erased. From an article at Wired: 'Problem is, even if you do everything right, there can still be lots of personal data left behind. Simply restoring a phone to its factory settings won't completely clear it of data. Even if you use the built-in tools to wipe it, when you go to sell your phone on Craigslist you may be selling all sorts of things along with it that are far more valuable — your name, birth date, Social Security number and home address, for example. ... [On a wiped iPhone 3G, mobile forensics specialist Lee Reiber] found a large amount of deleted personal data that he recovered because it had not been overwritten. He was able to find hundreds of phone numbers from a contacts database. Worse, he found a list of nearly every Wi-Fi and cellular access point the phone had ever come across — 68,390 Wi-Fi points and 61,202 cell sites. (This was the same location data tracking that landed Apple in a privacy flap a few years ago, and caused it to change its collection methods.) Even if the phone had never connected to any of the Wi-Fi access points, iOS was still logging them, and Reiber was able to grab them and piece together a trail of where the phone had been turned on.'"
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Wiping a Smartphone Still Leaves Data Behind

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  • by Anonymous Coward on Tuesday April 02, 2013 @03:44PM (#43341871)

    Did the previous owner use the "erase all content and settings" feature of that phone? Or just restore it. That would have been using the built in tool and would have overwrote the data. http://support.apple.com/kb/ht2110

    • by perpenso (1613749) on Tuesday April 02, 2013 @03:57PM (#43342015)

      Did the previous owner use the "erase all content and settings" feature of that phone? Or just restore it. That would have been using the built in tool and would have overwrote the data. http://support.apple.com/kb/ht2110 [apple.com]

      The author used the last iPhone (3G) running the last iOS version (4) that would exhibit such behavior. It seems a contrived test.

      An upgrade to iOS 5 would fix the problem on the 3G. On newer phones the encryption key needed to access the data is destroyed, so the problem never would have occurred.

      • EXACTLY. Wish my mod points hadn't expired.
      • by ejasons (205408)

        The author used the last iPhone (3G) running the last iOS version (4) that would exhibit such behavior. It seems a contrived test.

        More than just contrived, it is very intellectually dishonest...

      • by Alter_3d (948458) on Tuesday April 02, 2013 @04:07PM (#43342149)

        The author used the last iPhone (3G) running the last iOS version (4) that would exhibit such behavior. It seems a contrived test. An upgrade to iOS 5 would fix the problem on the 3G. On newer phones the encryption key needed to access the data is destroyed, so the problem never would have occurred.

        Sorry, but the iPhone 3G tops out at version 4.1.2. The 3GS, on the other hand, does have support for iOS 6, if I remember correctly.

        • by Bigbutt (65939)

          Yep. I have 6 on my 3GS. The first gen iPad doesn't though.

          [John]

        • by perpenso (1613749)

          The author used the last iPhone (3G) running the last iOS version (4) that would exhibit such behavior. It seems a contrived test. An upgrade to iOS 5 would fix the problem on the 3G. On newer phones the encryption key needed to access the data is destroyed, so the problem never would have occurred.

          Sorry, but the iPhone 3G tops out at version 4.1.2. The 3GS, on the other hand, does have support for iOS 6, if I remember correctly.

          My bad. I might have been thinking of the iPod 3rd gen which tops out at 5.1. The iPhone 3GS (also 3rd gen) is supported by iOS 6.1, the current version.

      • As others have pointed out, the iPhone 3G topped out at iOS 4 (and that's if you can't deal with how slowly it ran). Even if it could run iOS 5, you neglected the possibility that the person could have sold the phone before iOS 5 even came out. My iPhone 3G definitely had no such erase option and since the damn phone refuses to mount like a proper USB device, I was not able to use software from my laptop to securely wipe the phone before selling it. Oh well, at least I haven't had my identity stolen yet.
        • After erasing the contents fill the 3G with music to overwrite, then erase again?
      • But you're assuming that everyone who had an older phone ran out and ditched it the moment the new ones came out and thus there are no older iPhones with older software in use.

        Oh wait... we're talking about Apple. Ok, yeah, everyone DID immediately ditch their old phone the moment the new model came out. Nevermind.

        • But you're assuming that everyone who had an older phone ran out and ditched it the moment the new ones came out and thus there are no older iPhones with older software in use.

          Oh wait... we're talking about Apple. Ok, yeah, everyone DID immediately ditch their old phone the moment the new model came out. Nevermind.

          Its been nearly 3 years since the 3G has been sold. Both iPhone and Android users tend to have phones less than 3 years old.

      • So? (Score:4, Insightful)

        by ArchieBunker (132337) on Tuesday April 02, 2013 @04:37PM (#43342441) Homepage

        This was to prove that selling your OLD PHONE can raise security issues

      • by djl4570 (801529)
        No so contrived. These are the phones that are entering the used market. The early adopters are getting the next great iPhone and selling their old one. A lot of these users don't want to spend time or money upgrading the OS of an old phone and may be blissfully unaware of the security issues of the outdated OS.
      • by Lumpy (12016)

        It was also a iphone 3, the 3G and newer all solved this problem. The Article is horribly out of date.

  • Most decent cell phones have built-in encryption which wipes the phone by simply deleting the built-in keys. Some cheap-ass droids and the 'feature-phones' may not have it built-in but it's fairly easy to wipe a phone that has the feature.

    Off course, if you use the wrong methods (such as simply 'restoring' the phone) or using unencrypted external media, not much is going to help you. If you really need to get rid of your data (eg. in an enterprise environment) I would hope those in charge of the devices would know how to configure and manage the phones correctly so they can be remotely wiped etc

    • Re: (Score:3, Informative)

      by Anonymous Coward

      The bad news is that only since Android 4.0 that there has been decent encryption in devices. Before that, only some Motorola devices had some ability to encrypt the SD card and the main filesystems.

      The good news is that Android has grown up, and uses dmcrypt to encrypt the /data partition. One can even have the passphrase that decrypts the filesystem separate from the screen unlocking PIN, using a command line and the vdc cryptfs changepw command. This way, if the device falls into the wrong hands and g

      • by h4rr4r (612664)

        If you are reselling the device just remove the SD card, or stick it in a PC and use DD to write /dev/urandom to it. Obviously some users will find the latter approach too technical, or not trust SD cards enough, so selling it without an SD card is a fine solution.

        • by gl4ss (559668)

          that just takes care of the sdcard though and leaves the internal rom untouched. wiping that is a possibility too though.

          doesn't sound like the phone in the article was wiped at all though.

    • Phones with no encryption could just "dd if=/dev/zero of=/dev/mmcblk0" or equivalent. It's just a matter of user-ignorance, not of software issues.

  • by kallisti (20737) <rmidthun@yahoo.com> on Tuesday April 02, 2013 @03:54PM (#43341997) Homepage

    The key line: "On a wiped iPhone 3G"

    Starting with the iPhone3GS, iOS encrypts everything with a random AES256 key. When you say to wipe the device, it erases that key rendering everything else unusable. This is mentioned in the article, but downplayed. It's been a long time since you could even buy an iPhone 3G, so it seems alarmist to bring it up now.

    http://blog.itsecurityexpert.co.uk/2011/10/securely-wiping-your-personal-data-from.html [itsecurityexpert.co.uk]

    • by PyroMosh (287149)

      For real.

      I get why that could be a problem with a PC. After all, it's not unusual to file one's taxes on one's PC, or have other records that might include one's SSN on a PC. But who the hell is doing anything like via a phone?

      • by h4rr4r (612664)

        TurboTax and other have products that work on smartphones and tablets. I do not believe they save anything like that locally though.

  • Newer phones (Score:4, Interesting)

    by Selfbain (624722) on Tuesday April 02, 2013 @03:57PM (#43342017)
    I'd be more interested to see if he can still do it on a newer model. The earlier models of iPhones were well known to have poor security.
  • we rounded up every old phone we could scrounge up from around the office and asked the owners to wipe them. Our stash consisted of two iPhone 3G models, two Motorola Droids, an LG Dare and an LG Optimus.

    There were similar discrepancies in what Reiber found on the two iPhones, although both were 3G models running iOS 4

    It’s worth noting that the iPhone 3GS and newer versions use a hardware encryption key which is deleted when the phone is wiped, but data was easily recovered from these older models.

    Oh no! Five-year-old* long-discontinued phones running old OSes lack security! The horror!

    * okay, the Droid is only 4 years old, and the Optimus a mere 3. (And both shipped with Android 2.0 or earlier.)

  • 'Smartphone' is a general term, but this article is about specific smartphones. "Our stash consisted of two iPhone 3G models, two Motorola Droids, an LG Dare and an LG Optimus. (We had hoped for a BlackBerry, but nobody had one.)" As usual, BlackBerry is not only excluded from the test, but the technology 'journalists' had to throw in a swipe at BlackBerry, which, to me, is an admission of their own incompetence. A BlackBerry device probably would pass the test with flying colors, just as these devices do w
    • by h4rr4r (612664)

      Or maybe it reflects the fact that few people still use them, and nearly no one would if they had a choice.

      Most modern smartphones support good encryption. Just use that.

      • So your argument is that the LG Dare is a more popular phone and platform than BlackBerry? You are wrong.
        • by h4rr4r (612664)

          No my argument is that the LG dare might have been more popular than any single Blackberry at one time.

  • While referring to getting all data erased.

    'Problem is, even if you do everything right, there can still be lots of personal data left behind.

    Wouldn't that mean you just didn't do everything right? Huh?

    Google doesn't help matters by providing no avenue for de-linking one's no-longer-owned device from an existing [Google Play] account. Sad.

  • by Andy Dodd (701) <atd7&cornell,edu> on Tuesday April 02, 2013 @04:02PM (#43342085) Homepage

    The article makes no mention of WHICH Android revision each of the given phones tested was using.

    It was a known problem with Gingerbread and earlier that the wipe method used by most Android devices was insufficient. That's why Google added secure erase prior to reformat with ICS (maybe HC too, not sure...)

    https://android.googlesource.com/platform/system/extras/+/c2470654d4b4db09a7052fc5fa108ac21f1b1948 [googlesource.com]

    Interesting result of this: Samsung's eMMC chips that were shipped in the Galaxy S II and original Galaxy Note couldn't handle this secure erase command properly, and using a standard "secure" wipe had a pretty good chance of corrupting the wear leveller so badly the chip would be rendered useless. (Samsung's own recoveries were "neutered" so as not to issue a secure erase command.)

    TL;DR - Unless crippled by the manufacturer, any recent Android device (ICS or newer) should not have any of the issues with data remaining easily recoverable after a wipe described by this article. LG didn't do anything special here - they just implemented ICS or later and that's all that was needed.

  • Van der Graaf Generator?
    Oxy-acetylene torch?
    Cement kiln?

    I know what to do with a hard drive (DBAN followed by drill press) and a DVD (shredder).

  • How the hell on EARTH do you have "61,202 cell sites" without de-duping?

    Then I checked the US wireless quick facts and found:
    June-12 June-07 June-02 June-97
    285,561 210,360 131,350 38,650

    Yikes, that's quite the expansion... but regardless, it still means this phone would've travelled through a very large number of dense American cities to get up to that count.

  • pound it to smithereens with an 8 pound sledge hammer, nothing but crumbs left when i am done
  • Destroy it instead. It's enormously gratifying to reduce a smart phone to powder. And try reading that.
  • by Anonymous Coward

    Once again, blackberries solved this problem about 10 years ago (or more).

    If you want real, audited, certified security, get a blackberry.

    If security isn't important to you, android & iphone are fine.

    Sadly, most people are in the latter category.

  • by Grand Facade (35180) on Wednesday April 03, 2013 @06:21AM (#43346267)

    "Will it blend?"

Line Printer paper is strongest at the perforations.

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