Slashdot Mirror
Wiping a Smartphone Still Leaves Data Behind
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.'"
That's why I used a sledgehammer and a group of beefy muscular friends to wipe mine out. 7 in fact.
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
Now there is a burgeoning career field. Does this still work after clearing the cache on and Android?
Why would my phone know my social security number? Has anyone ever had to input this?
take the point of the article, as it were, but you'd have to move pretty fast for 68,000 wifi points that you had connected to. pretty fast.
This wouldn't be an issue if cell phones were unlocked and the firmware and OS was GPLed.
Without the development of a secure wipe tool for mobile devices, all your information is easily available to retrieve as long as you know what you are doing. Look up tools like FTK or Encase.
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
Custom electronics and digital signage for your business: www.evcircuits.com
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
on their phone??
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
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.
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.
Well, it has never been successfully tested.
EXACTLY. Wish my mod points hadn't expired.
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.)
How can I believe you when you tell me what I don't want to hear?
http://www.accessdata.com/products/digital-forensics/mobile-phone-examiner On-the-Fly Decryption of Operating System and Logical Data of iOS
'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 with most every security test. I'm not claiming that BlackBerry should be best selling phones or that they are the greatest ever, just that credit should be given where it is due.
I once took an excursion to Reddit, and later HN. Unlimited up/down voting sucks when dealing with a hive-mind.
I've read in a few places that if you enable encryption on either Android or an iPhone, it encrypts the entire flash chip at a low level, which has pretty much the same effect as writing a disk with random data if you don't know the key. These articles therefore recommended the following process to sanitize your phone before reselling/discarding it:
1) Enable encryption
2) Perform a factory reset/wipe
3) Disable encryption
4) Repeat if paranoid
That way all your data is deleted, and all "deleted" files are scrambled and impossible to recover if you don't have the key.
It doesn't look like researchers looked at phones where that had been performed.
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.
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
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.
retrorocket.o not found, launch anyway?
I'm guessing that only works if the phone wasn't reset to factory settings.
More than just contrived, it is very intellectually dishonest...
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.
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).
What part of "wipe device resets the key" did you not understand? You can't recover anything if the key is discarded. That article only matters for police who have recovered iPhones from criminals and want to try and get something out, not people who are selling a phone and reset it beforehand.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
Yep. I have 6 on my 3GS. The first gen iPad doesn't though.
[John]
Shit better not happen!
You can't "fight back" when the encryption key has been discarded. It is gone.
That misunderstood article is about how to get data off a device that has NOT been wiped.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
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.
Bye!
just stick the phone in a degausser......
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.
Which begs the question: "How do blind people know when to stop wiping?"
Solving Unix problems since 1989...
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.
Erase hard drive= sledgehammer+fire.
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.
This space available.
even in an ssd or usb storage device, flash memory is a bugger to erase... and to know with absolute certainty that the data is indeed gone, requires destruction, not deletion.
I know that many blind people fill cups with liquid by putting a finger in the cup, and feeling when it's full. Maybe they use the same sense of touch in this case ....... I've got to stop shaking blind people's hands.
Quick, someone tell 2008 that they have a problem with phone security.
I tried to call the iPhone owners but they were all on AT&T and had no reception.
Then I tried to call all the Android owners but their batteries were all dead...
"There is more worth loving than we have strength to love." - Brian Jay Stanley
Which begs the question: "How do blind people know when to stop wiping?"
Blind people don't wipe.
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.
This was to prove that selling your OLD PHONE can raise security issues
Only the State obtains its revenue by coercion. - Murray Rothbard
pound it to smithereens with an 8 pound sledge hammer, nothing but crumbs left when i am done
Politics is Treachery, Religion is Brainwashing
How many times are you going to quote that article without understanding WTF you're quoting? And you call yourself a CEH?
Jesus Christ.
After erasing the contents fill the 3G with music to overwrite, then erase again?
Pretty sure the filesystem in iOS can have partially empty blocks. I'd make a copy of my music, then run find . -type f -print0 | perl -n0e 'truncate($_, -s $_ >> 13 13)' to make sure that all the files were rounded off to 4096 bytes first.
I just thought to check for apps that wipe storage, there are several. I should have known there was an app for that. :-)
The author used the last iPhone (3G) running the last iOS version (4) that would exhibit such behavior. It seems a contrived test.
It's only contrived if you fail to consider that most people who are SELLING a USED iPhone on Craigslist are selling their OLD model, not the new one they just purchased.
Personally, I found the following statement the most interesting out of the entire article:
"Interestingly, many of the locations found in the database were places the phone’s owner had never been — most in southeast Asia. Reiber says this suggests the phone or its memory had been refurbished"
That's very interesting indeed.
It could have been in an email:
* State/gov authorities.
* Insurance company.
* Your doctor
* Digital copy of payslip
etc.
Do you not have access to your email via your phone?
"We mustn't be caught by surprise by our own advancing technology" -- Aldous Huxley
Or the wi-fi access point MAC address was duplicated by some cheap SE Asian company?
I'd say there is a higher probability the location data was just wrong.
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.
Actually, I was wrong, I misunderstood somethings. Not afraid to admit I was wrong.
Is this encryption key stored in multiple places on the device? In case of accidentaly corruption or hardware error?
Also, another question. Is the encryption key backedup onto the computer when you make a backup, or is the device the only copy in existence anywhere of they key?
And all I can say is "DUH!" This is nothing new. The iPhone 3 did not have the built-in support to encrypt the personal data partition used on the phone, because that feature did not exist on the iPhone until iOS version 4, which coincided with the release of the iPhone 4. The iPhone 3 could not be upgraded to iOS 4.x, though the 3GS could, so this is no big surprise. Fun fact: when you wipe a iOS 4.x and later device, it doesn't actually wipe the data. What it does is destroys the encryption key for the encrypted partition, rendering it unreadable.
Destroy it instead. It's enormously gratifying to reduce a smart phone to powder. And try reading that.
It was also a iphone 3, the 3G and newer all solved this problem. The Article is horribly out of date.
Do not look at laser with remaining good eye.
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.
This is news at Slashdot in the year 2013? Are we starting to see a pattern here or is it just my imagination?
When you wipe so hard it causes you to sneeze, you can stop.
You have the right to remain sentient. If you give up the right to remain sentient, you will be elected to public office
I'm actually impressed. Good for you.
The author used the last iPhone (3G) running the last iOS version (4) that would exhibit such behavior. It seems a contrived test.
It's only contrived if you fail to consider that most people who are SELLING a USED iPhone on Craigslist are selling their OLD model, not the new one they just purchased.
The 3G is not simply an old model, its an obsolete model. Many actively supported apps won't support its CPU (armv6), amount of RAM (128MB), or OS version (4.2.1). The 3G was replaced by the 3GS nearly 4 years ago, it sales slowed before that due to the impending release of the 3GS, and it has not even been offered as a low end budget alternative for nearly 3 years. I expect the used iPhones being sold today are generally iPhone 3GS or 4, phones that are supported by the current version of iOS and actively supported by apps.
Now if you want to complain that a phone sold 3 years ago is obsolete, well that is a different topic and I'm likely to agree with you. But with respect to the topic of today's used iPhone market, focusing on the 3G does seem contrived for the reasons above.
To avoid redundant posts ... http://slashdot.org/comments.pl?sid=3607997&cid=43344171
Horribly contrived. The iPhone 3G came out 5 years ago and was the last version of the phone that was susceptible to this. This was a widely-known problem at the time, which is why Apple fixed it.
If not contrived, it's horribly intellectually dishonest to pull out a known issue from 5 years ago and trot it out as if it's a new vulnerability.
Their heightened sense of smell?
I guess I'd try rm -fr / on my clockworkmod terminal and then tried to flash vanilla android there...
The dog stops licking.
English is not this
"Will it blend?"
Rick B.
Next question?
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"