How do you clean a computer thoroughly leaving no evidence on it?

samthehacker · #1 (**permalink**) 10-04-2009, 10:54 PM

The clean needs to be clean enough so the jakes are left scratching their heads. I know its possible aswell. Does anyone want to share methods. Ill probably post a little tut later on. If there isnt already one.

shetlan · #2 (**permalink**) 10-05-2009, 12:30 AM

Quote:

Originally Posted by samthehacker

The clean needs to be clean enough so the jakes are left scratching their heads. I know its possible aswell. Does anyone want to share methods. Ill probably post a little tut later on. If there isnt already one.

If you want to erase absolutely everything, the only way I've ever heard of (that actually worked) is a large magnet.

Bahr · #3 (**permalink**) 10-05-2009, 02:49 AM

Strip out every thing on the insides and replace it. So its a new computer in the same shell.

Shepherd · #4 (**permalink**) 10-05-2009, 02:56 PM

The magnet trick is pretty effective, but leaves evidence that you are hiding something. Over-write the hard drive using the original program disks. Do this three times. This will remove everything that had been previously done on the computer, and there is no real evidence that you are hiding anything.

There are also pirate programs out there that will re-write your hard-drive if youdo not enteer the correct password. This one is dangerous if you ever mis-type your passwod!

Personally, I perform all of my computer actions through a program on an external hard-drive. That way there is no evidence of on-line cookies or websites on the computer itself. The external hard-drive is encrypted and is program protected as well. If the wrong password is entered twice, the program executes and over-writes. My financials and personal files are not used on a computer that is connected to the internet, so hacking and pirating are not an issue.

ninefingers · #5 (**permalink**) 10-05-2009, 03:53 PM

The DOD has some program (forgot the name--will call Arturo about it) that writes all 0's to the HDD; then all 1's to make sure all is gone. HDD's from Raytheon (they make missiles)that are discarded and sent to salvage yards must all go through this

Of course, Raytheon also drills 5 holes through the plattens ("disks") to demilitarize them...they make good wind chimes, after that.

spunone69 · #6 (**permalink**) 10-05-2009, 04:20 PM

The magnet works best...find an old car speaker (like a 6" X 9") and break the magnet off the back of it, then just leave it sitting on the hard drive for about 10 - 15 min...it will render the hard drive useless, but no one will be able to recover anything from it!! The DOD program is called "Boot & Nuke" and it will wipe the drive with all zero's up to seven times (and it takes HOURS!!) It is available in the UBCD boot disk which can be found numerous places on the net. Just google "UBCD" and you'll find it...don't use the Windows version, use the CD bootable .iso image. There are a number of hard drive "wiping" tools in this program. Your best bet, if you're worried about someone "finding" your data is to remove the RAM and Hard Drive and replace them with brand new (not used) stuff!!

samthehacker · #7 (**permalink**) 10-05-2009, 06:22 PM

Is it possible to divert all browsing evidence to a flash drive. Im talking about things such as browsing history, cookies, temporary internet files etc.

spunone69 · #8 (**permalink**) 10-05-2009, 10:00 PM

I don't know what you mean by "divert"...it is possible to "copy" all the browsing history, cookies etc...if you're "wiping" the whole hard drive, why would the history matter??

spunone69 · #9 (**permalink**) 10-05-2009, 10:03 PM

If you use the "back-up" feature in Windows before you wipe it, it will allow you to save all the stuff you're talking about. But don't you think that "saving" anything kind of defeats the purpose of "wiping all evidence"?? If you don't want any evidence left from the hard drive...don't save anything!! DUH!!

thatcaffinatedguy · #10 (**permalink**) 10-06-2009, 12:24 AM

Ok you could try Cyber Scrub?

I'm told that's a pretty decent wiping program.

Or As i said in another post Tune-up Utilities has a REALLY good erasing program on it if your keen to download. It costs like $30 US but there are torrents for it aswell.

But I'm quite partial to the magnet idea lol

Syphilis · #11 (**permalink**) 10-07-2009, 01:03 PM

Download the DBAN live CD. Burn it onto a CD and boot the computer from it. Select the DoD 7 pass erase. Job done.

pcypoon · #12 (**permalink**) 10-09-2009, 04:08 AM

A simple format won't wipe out all the information, it can still be easily retrievable. (So moving it to a usb, will not work) Deleting something means that the OS removes the directory of where the file is located. The file still physically exists on the hard drive until something is overwritten on that part of the hard drive.
Well on the matter of cleaning, it takes quite some time to completely wipe out a hard drive. Aforementioned, there are plenty of programs that can make sure all files are gone by re-writing over and over it but they all take a long time. ( 3 - 4 hours for the simple format, replacing all values to 0, but there are still patterns where it can be reverse engineered to retrieve the information
There are some bootable programs where it literally over writes it many times with patterns so that data recovery is slim to none, these can take a long time.

If time is an issue, taking out the platters and fry it with a blow torch, takes approximately, 10 minutes.

Just as a safe measure, you can encrypt your hard drive with AES 256 encryption. Law enforcement won't bother trying to decrypt it, it would cost too much for them to do so. (Unless your some kind of serial killer)

In my opinion if you want to be safe, is to have AES 256 encryption is the best bet.

Oh and for browsing history, there are programs/add-ons where it prevents all the information from being stored. If it is ever stored and is not properly overwrite, it will always still be able to retrieved.

needzhelp · #13 (**permalink**) 10-10-2009, 12:51 AM

Quote:

Over-write the hard drive using the original program disks. Do this three times. This will remove everything that had been previously done on the computer, and there is no real evidence that you are hiding anything.

civilian programs can bring back info from 3 overwrites but the government can bring back info from 7 complete overwrites...the best way leave no evidence is smash your hard drive and get a new one.

shetlan · #14 (**permalink**) 10-10-2009, 10:25 AM

Quote:

Originally Posted by needzhelp

civilian programs can bring back info from 3 overwrites but the government can bring back info from 7 complete overwrites...the best way leave no evidence is smash your hard drive and get a new one.

Smashing a hard drive doesn't do much of anything if you're up against any worthwhile agency or opposition force. With the proper equipment and resources, data can be recovered from a drive that's been smashed to bits. Everything is still there, you just need to put it back together.

needzhelp · #15 (**permalink**) 10-10-2009, 05:32 PM

Quote:

Smashing a hard drive doesn't do much of anything if you're up against any worthwhile agency or opposition force. With the proper equipment and resources, data can be recovered from a drive that's been smashed to bits. Everything is still there, you just need to put it back together.

i dont know man....putting a smashed drive back together may be impossible, hard drives are made of aluminum or titanium, are supposed to unbend, the pieces of metal then weld them together or glue them, but if im wrong just to be safe throw the bits of your hard drive into a fire, heat will finish the job certainly.

`sIn · #16 (**permalink**) 10-11-2009, 05:14 AM

BBC NEWS | Technology | Hard drive destruction 'crucial' ...watch the vid

shetlan · #17 (**permalink**) 10-11-2009, 05:25 AM

Quote:

Originally Posted by needzhelp

i dont know man....putting a smashed drive back together may be impossible, hard drives are made of aluminum or titanium, are supposed to unbend, the pieces of metal then weld them together or glue them, but if im wrong just to be safe throw the bits of your hard drive into a fire, heat will finish the job certainly.

Smashing a hard drive is no different from taking all the pages out of a book and spreading them around a room. You can still recover the information, you just need to gather the pieces.

I've seen info from hard drives recovered after bomb blasts - it's complicated, time consuming, and apparently requires some pretty specific equipment, but it can be done if one is so inclined.

Syphilis · #18 (**permalink**) 10-12-2009, 05:28 AM

Quote:

Originally Posted by needzhelp

civilian programs can bring back info from 3 overwrites but the government can bring back info from 7 complete overwrites...the best way leave no evidence is smash your hard drive and get a new one.

Absolutely 100% incorrect. The most data ever successfully recovered was 4KB of data which had been overwritten by a single pass. It was done with magnetic force microscopy.

Quote:

Originally Posted by `sIn

BBC NEWS | Technology | Hard drive destruction 'crucial' ...watch the vid

Whoever wrote that article has no idea what they are talking about. Of course files can be recovered if you've just done a simple delete. I don't think they've ever heard of overwriting files before...

EDIT: Just read the entire article. Don't listen to a word they say. Seriously, nearly EVERYTHING is wrong.

Quote:

Originally Posted by shetlan

Smashing a hard drive is no different from taking all the pages out of a book and spreading them around a room. You can still recover the information, you just need to gather the pieces.

I've seen info from hard drives recovered after bomb blasts - it's complicated, time consuming, and apparently requires some pretty specific equipment, but it can be done if one is so inclined.

Quote:

Originally Posted by shetlan

Smashing a hard drive doesn't do much of anything if you're up against any worthwhile agency or opposition force. With the proper equipment and resources, data can be recovered from a drive that's been smashed to bits. Everything is still there, you just need to put it back together.

Which is why you must overwrite the data. Then destroying the device is basically just a formality/lulz.

`sIn · #19 (**permalink**) 10-13-2009, 06:46 PM

Quote:

Originally Posted by Syphilis

Which is why you must overwrite the data. Then destroying the device is basically just a formality/lulz.

Wow you would really take a penitentiary chance on a software overwrite when you can get a tb internal for less than 80 bucks right now? Ignorant.

EDIT: If you've taken more than 50 hard drives apart and/or tried to recover data from head crashes then please reply, otherwise stfu. Open the hd casing, pull the platters out, and grind them to dust. Why chance it?

Misanthropy · #20 (**permalink**) 10-13-2009, 10:43 PM

^^^ What's up with ferret's alter ego posting now?

Quote:

Originally Posted by Syphilis

Download the DBAN live CD. Burn it onto a CD and boot the computer from it. Select the DoD 7 pass erase. Job done.

Bingo, if you plan on using it again. If not, delete if not secure shred, your info & hammer it.

Syphilis · #21 (**permalink**) 10-15-2009, 01:24 AM

Quote:

Originally Posted by `sIn

Wow you would really take a penitentiary chance on a software overwrite when you can get a tb internal for less than 80 bucks right now? Ignorant.

Quote:

EDIT: If you've taken more than 50 hard drives apart and/or tried to recover data from head crashes then please reply, otherwise stfu. Open the hd casing, pull the platters out, and grind them to dust. Why chance it?

You must be pretty ignorant of digital forensics to say that using an overwrite is "chancing it". It's not. It's paranoia, and not the good kind that keeps you safe, but the kind that is detrimental.

Like I said, the most data ever recovered to date was 4KB of contiguous data which had been overwritten by zeros only a single time.

Moral of the story: Use a 7 pass overwrite on sensitive data, and never store anything sensitive on a drive that is not encrypted.

thoughtcriminal · #22 (**permalink**) 10-20-2009, 07:14 AM

A lot of these replies are just laughable.

For most practical purposes, you'll want to overwrite each and every single byte on the hard drive a few times. There are a few programs out there to do this, most notably (if you're looking to overwrite EVERYTHING and leave it unusable until partitions are recreated and it's reformatted) is "Boot and Nuke". It is available as an ISO so you can burn it and boot it up, and it'll take care of business. The most basic type of write is overwriting each byte with the same pattern repeatedly until the disk is overwritten in it's entirety. DoD standards mandate seven passes (I believe) including a pass of zeroes, a pass of random data, and then certain passes of patterns. There's another method that does it 35 times.

Realistically, unless you're dealing with an equipped intelligence agency, you can get away with just one write of all zeroes. Boot and Nuke can handle this for you.

Visit Darik's Boot And Nuke | Hard Drive Disk Wipe and Data Clearing

Yours,

Thought Criminal

etc. · #23 (**permalink**) 10-27-2009, 11:59 AM

erm...a hammer?

The magnet method does definatly work though, i've accidentally done it before just by placing the magnet over my harddrive in my laptop. When I took the magnet away the laptop restarted but it was too corrupt to go past the initial boot screen.
However, I phoned the nice people as Dell and they sent a replacement drive and they gave one with a bigger capacity for the inconvenience.

-etc.

_JT_ · #24 (**permalink**) 11-19-2009, 01:02 AM

Due to the nature of how a hard disk works, it's very difficult to render the data completely irretrievable. I'm not going to speculate why you need to do such a thing, but whenever I move on, the hard drive(s) I was using at the time get dismantled, the platters removed and then physically destroyed, then the whole drive replaced with something dirt cheap with a suitably "used" looking XP install, with boring innocuous stuff in the documents folders.

It's handy to have a couple of swap-out drives stored away in case you need a quick switcheroo