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Memories of a Media Card
twistedmoney99 writes "Anyone who has upgraded their digital camera probably has a few older, incompatible media cards lying around — so why not post them on Ebay? Well, if you do, be sure to properly wipe them because the digital voyeurs are watching. Seth Fogie at InformIT.com purchased a bunch of used cards from Ebay and found recoverable data on most of them. Using the freely available PhotoRec application, he was able to extract pictures, movies, and more from apparently formatted cards. The picture is clear — wipe anything that can store digital data before getting rid of it."
It adds to the value on auction sites. A lot of people are willing to pay a fortune to see images of my dick.
Hm, haven't we had this story already with hard disks, some time ago?
dd from /dev/urandom onto the media multiple times ( in excess of 20 times if you are paranoid )
I'm not entirely certain it'd work on memory cards, but it works great on hard drives. You can overwrite clustertips, free space, etc. with many passes of psuedo-random data. I think the new version is commercial, so here's a link to an older version: http://www.tolvanen.com/eraser/
Don't quote me on this (I haven't gotten my RAZR yet, still waiting on UPS)...but from the specs I read, the memory card on the RAZR is removable, and the site said it also came with an SD adaptor so you can put the card in anything that can read SD cards. Currently the only thing I have with an SD reader is my Wii, so I can't really test this out even after I get my phone until I get an SD reader. Might be worth a shot though.
Memory cards do not have nearly as strong of a memory effect as hard drives. With a hard drive you can write and rewrite multiple times and still have data recovered by someone willing to spend the time, effort, and money. But memory cards are much harder. You could be relatively sure of safety if you just:
1. Delete everything on the card.
2. Fill the card with something not private (maybe a text file that just repeats the same character).
3. Delete everything on the card.
4. If you're paranoid do 2 and 3 again.
If you don't have a computer handy, you can accomplish step 2 by taking photos of a blank sheet of paper or a lenscap or something of that sort.
I've recovered photos by hand for family members who've accidentally nuked their memory cards (did it the hard way with a hex editor, dd and cut). So wouldn't dd if=/dev/random of=/dev/ memory-card bs=1K count= card-size-in-kib suffice?
After reading the article, I wondered how many of these cards are actually stolen?
And I don't mean Pamela Anderson and Tommy Lee stolen either.
I had a 4-month-old 250gb hard drive die of heatstroke within a fanless drive enclosure. The drive had, shall we say, material of an "educational" nature. (ahem)
Anyway, I didn't want to release said material to the general public at [insert HD manufacturer here], so I abandoned any warranty recovery and just physically destroyed the drive. So much for that $100.
As for erasing solid state media, I'd feel perfectly safe simply overwriting it with zeroes, one time over.
I realize years ago magnetic media were written sparsely (inefficiently) with sloppy positioning mechanisms, but those days are long gone. I'd be really impressed to see somebody recover overwritten data on a hard drive instead of just talking about it.
As for flash memory, I'll believe it when I see it.
As for leaking information through discarded camera memory cards in the first, place, it's about the 1000th thing down my list of privacy concerns, way down below "binoculars." If you want to see pictures of random people's snapshots of each other, they're all over the web. How many of us really use our digicams to capture super-secret info? I just can't bring myself to care when I know databases of thousands of credit card numbers and SSNs are being bought and sold on the black market.
I'm sure a lot of people don't wipe the camera cards because they don't care if someone gets photos of their pets or disney vacation or drunken stupor. They figure most people - ie. those not interested in writing an alarmist privacy article - will simply wipe and use the card. Unless you're a celebrity, or have a stalker why would you care? You're probably photographed more by traffic cameras these days anyway.
These posts express my own personal views, not those of my employer
If it's data you care about someone else getting a hold of, I would recommend using Thermite. It's a wonderful, all purpose, cleanser of just about everything.
Necessity is the mother of invention.
Laziness is the father.
Better (and more convenient) than dd'ing from /dev/urandom is wipe(1). It will, at your option, overwrite the disk using 34 different byte patterns, 8 of which are random.
Its man page is also the only one I know of that uses the phrases "rising totalitarianism", "Department of Homeland Security", and "THIS IS AN EXTREMELY DANGEROUS THING TO DO".
"What are the best methods for removing almost any record of data?"
Have Chuck Norris give it a roundhouse kick.
There are ten or fifteen posts here with people suggesting that people should use dd, or wipe to write over these removable media to stop people recovering the data. Most people seem to be suggesting doing a dd from /dev/random TWENTY times.
What I would like to know is what the most effective method is. Someone should take a bunch of these cards (and harddrives etc) and do a little controlled test to see how much of a photo/file is recoverable after one round of dd, after 10 rounds of dd, etc. In short - what's the most effective (time v.s. security) method for cleaning these things?
henry -- the human evolution news relay
> Its man page is also the only one I know of that uses the phrases "rising totalitarianism", "Department of Homeland Security", and "THIS IS AN EXTREMELY DANGEROUS THING TO DO".
Doesn't "man woman" also use those phrases? And for good reason, too...
When I first started at NASA the methodology was to use something like Norton's Erase, put it on Government Erase (three passes of writing first all ones, then all zeros, then all ones again, then doing half tracks). When Windows 98 came along we still used Norton's Erase but it had a different algorithm which was quite good too. When Windows 2000 came along we were no longer trusted to erase everything properly and we had to send the disk drives to a centralized location where they were wiped before being sold. When Windows XP came along we were told to just take a hammer to them. This was because the government had made so many cutbacks that there wasn't any money to properly erase the disk drives.
:-/
On a side note: When I first started working at NASA we had a budget of well over a million dollars. We got rid of all of the really big mainframes, and minis, and went to micros. Our budget was reduced to somewhere around $500,000.00 a year (about a third of what we originally were given each year). What I'd like to know is - whatever happened to all of that money? We certainly never go pay raises which equaled the amount of money lost. So where did it go? The answer might be a bit more surprising than anyone really wants to know about.
Someone put a black hole in my pocket and now I'm broke.
Something like "wipe" is needed for rotational magnetic media. For flash, a simple cat /dev/zero > /dev/sd... is sufficient.
{sigh} This has been discussed before. The DoD's standards for highly classified computers amounts to a very large hole-punch and an incinerator. The "standards" you refer to amount to the wiping they do on receptionist and non-classified computers.
BD Phone Home!
Shameless plug. Like you weren't expecting it.
http://www.zdelete.com/dod.htm
The DOD already answered this question.
Whenever there's any doubt, DOD standards are the way to go.
This signature does not exist. It has never existed. It is all a figment of your imagination.
Modern storage systems either forget what they're supposed to remember, just when you need it the most ... or they remember it long after it is best forgotten.
The higher the technology, the sharper that two-edged sword.
If you can't boot the phone you can't clear it. Motorola phones have two settings, a MASTER RESET and a MASTER CLEAR that collectively clear all data and settings from the phone. The memory card in the V3i is used only for ringtones, video and such - phone numbers are still stored to SIM or Phone.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Maybe that's why they laid me off two weeks ago. :-(
I've been using Eraser for years. What more could you want? DOD & better wipe capability, secure move, right click context menu, erasing report and all for the low, low price of FREE!
In a nutshell, for hard drives, "If commercially-available SPM's are considered too expensive, it is possible to build a reasonably capable SPM for about US$1400, using a PC as a controller". So it is in the reach of the hobbyist to recover up to around the last 20 items recorded on any magnetic media (easier for floppies, harder as drives become denser). On solid state memory, I believe an electron microscope is needed for analysis. Still, data that has been in one location in RAM for more than five minutes is in theory recoverable.
Why would I not post them on eBay, even if wiped?
Aren't there data recovery services that recover data from supposedly wiped media (hard drives, memory cards, etc.)?
Besides, how likely are you to to make back the listing fees on used media? Given how the prices are coming down, why would you buy used when you can buy new for only a little more? Brand new 1 GB CF is going for $10, why buy used?
I would be worried that I would lose money selling used memory media on eBay; it would make more sense moneywise to just smash them with a hammer; get some exercise, and anything that was on them is now unrecoverable.
Government's idea of a balanced budget: take money from the right pocket to balance...oh who am I kidding?
I mean seriously, the discussion shouldn't be about "proper erasure techniques that 99.999% of the public couldn't understand if they tried", it should be about not being such a tight-ass cheap fuck that you have to sell your old drives (flash / hard / whatever) on E-Bay. I mean, seriously, do you need to spend that much effort to net yourself an extra $5 or $10?
I erase my old media with a sledgehammer. Try to recover that, bitch.
Help save the critically endangered Blue Iguana
DRM 'manages access' in the same way that a prison 'manages freedom'
Throwing away or destroying manufactured items when they are working and reusable is irresponsible, because it does not attempt to minimize environmental impact.
Used items that are still in demand should be reused as much as possible, to reduce the demand for manufacturing these items (with all the power and waste involved in that) and the size of landfills.
Your signature vexes me:
Aych tea tea pea colon slash slash dot dot org slash
h t t p : / / dot . org /
Unless your signature is advertising some link farming site, I think you have a missing slash.
I'd just keep the damn thing. You know that as soon as you sell it you'll have a desperate need for it. That's just how the world works.
Much of the information in the article about data recovery is also covered by DebianAdministration.org. TestDisk and photorec, are afterall, free software.
Hip, hip hooray!
DMCA, Hollings, Palladium. What might have sounded like paranoia is now common sense.
From the paper: (blah blah blah)
I don't normally waste bandwidth or other resources commenting this way ("Me too! Me too!"), but I have to tell you that was the most kick-ass summary and explanation of the problem. Thank you for knowing an intelligent and concise technical reason for seemingly (and massively) redundant re-writing, thank you for having it handy, thank you for citing the most useful passage, and thank you for posting.
Damn, I never have mod points when I need them. I'd have dumped all of them on that posting if Slashcode would let me. +5: "The Poster Credibly Could Have Written A PhD Dissertation On What S/He's Talking About".
Fire and Meat. Yummy.
Here is a tried and trusted method:
http://en.wikipedia.org/wiki/Gutmann_method
it is only after a long journey that you know the strength of the horse.
I commit to not smashing ~1 memory card a year the second you get every(hell, some of them) Jim-Bob to stop driving his V8 100 miles to work everyday.
Nerd rage is the funniest rage.
From the article:
In addition, the fact that some of the cards contained undeleted images is a bit disconcerting. At a bare minimum media card owners should have deleted the viewable images.
Why? Why should they have, if they don't care who saw them? As they said, the images were all of clothed people and disney world and things, worth nothing to anyone but the owner.
Privacy just for the sake of privacy seems to have taken hold of too many people, who do not stop to think - is there any point to privacy in this instance?
Obviously if people did not want images being seen they should remove them; I just object to catiioning users against leaving images with the vague fear that "someone may see thier images" when that may not matter at all.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
Throwing away or destroying manufactured items when they are working and reusable is irresponsible, because it does not attempt to minimize environmental impact.
And burning who knows how much gasoline in order to physically transport an object across the country that weighs something around 2 grams is not irresponsible?
What would be responsible is giving it to an acquaintance or selling it locally on something like Craigslist. Putting it on eBay and shipping it to somebody who may be thousands of miles away is stupid.
Just use http://ncrypt.sourceforge.net/ to wipe data. It offers Gutmann and Military grade wipes.
And burning who knows how much gasoline in order to physically transport an object across the country that weighs something around 2 grams is not irresponsible?
Except that it's not as if the shipping company is making a special trip just to transport that one object. The amount of additional gasoline or jet fuel required to transport another 2g is miniscule.So, in order of preference:
reuse yourself
give/sell locally
give/sell distantly
destroy
There are other options as well, I'm sure.
> As for erasing solid state media, I'd feel perfectly safe
d f
> simply overwriting it with zeroes, one time over.
For most purposes, this might be perfectly enough.
Certainly an "all-zero" overwrite is far better than a "all-one" overwrite (flash erase operation). But then again it also depends on the controller, because what ends up in the floating gates is what really counts.
See link (below) for some techniques to recover erased or overwritten flash memory. The basic idea is to measure the trapped charge in each cell with higher resolution than just 1/0. In other words: as analog voltage. Since you can't just connect a voltmeter to each gate, you have to trick the read-out circuitry to forward (reveal) this information to you. The document is about how this can be done with some popular chips.
At first these techniques seem to require very invasive access to the memory. But once working, many attacks can be vastly simplified (see TV card scene).
http://www.cl.cam.ac.uk/~sps32/DataRem_CHES2005.p
Regards,
Marc