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DannySmit n00b

Joined: 12 Nov 2012 Posts: 1
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Posted: Tue Nov 13, 2012 1:56 pm Post subject: Good software to delete my personal files |
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| Hey all, I was wondering whether anyone could advice some good free sotware which I could download - I need to clean uo my work laptop from my personal files. Thanx! |
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John R. Graham Administrator


Joined: 08 Mar 2005 Posts: 6443 Location: Somewhere over Atlanta, Georgia
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Posted: Tue Nov 13, 2012 1:58 pm Post subject: |
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Moved from Other Things Gentoo to Off the Wall. Not about Gentoo so it fits better here.
- John _________________ This space intentionally left blank. |
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MustrumR n00b

Joined: 15 Nov 2011 Posts: 35 Location: Right here
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Posted: Tue Nov 13, 2012 2:36 pm Post subject: |
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| Code: | | dd if=/dev/urandom of=/dev/sda bs=4K | 4 or 5 times? |
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Prenj n00b


Joined: 20 Nov 2011 Posts: 7 Location: Mostar, BiH
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aidanjt Veteran


Joined: 20 Feb 2005 Posts: 1101 Location: Rep. of Ireland
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Posted: Tue Nov 13, 2012 4:37 pm Post subject: |
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man shred(1), is part of coreutils on Linux. If you don't want to be left at the mercy of the filesystem, then you're going to have to go though a bit more effort to calculate the sector range(s) of the file and zero with dd and seek with the raw disk and count to stop at the end of file, although that's very very risky if you don't know what you're doing, so just stick with shred. _________________
| juniper wrote: | | you experience political reality dilation when travelling at american political speeds. it's in einstein's formulas. it's not their fault. |
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energyman76b Advocate


Joined: 26 Mar 2003 Posts: 2022 Location: Germany
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Posted: Tue Nov 13, 2012 5:58 pm Post subject: |
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| MustrumR wrote: | | Code: | | dd if=/dev/urandom of=/dev/sda bs=4K | 4 or 5 times? |
even once is overkill.
FACT: overwriting a disk with ZEROs ONCE is enough. _________________
| AidanJT wrote: |
Libertardian denial of reality is wholly unimpressive and unconvincing, and simply serves to demonstrate what a bunch of delusional fools they all are.
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Satan's got perfectly toned abs and rocks a c-cup. |
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NotQuiteSane Guru


Joined: 30 Jan 2005 Posts: 470 Location: Klamath Falls, Jefferson, USA, North America, Midgarth
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Posted: Tue Nov 13, 2012 7:00 pm Post subject: |
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Nuke it from orbit.
NQS _________________ These opinions are mine, mine I say! Piss off and get your own.
As I see it -- An irregular blog, Improved with new location
To delete French language packs from system use 'sudo rm -fr /' |
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djdunn l33t


Joined: 26 Dec 2004 Posts: 617 Location: Under the moon and all the stars in the sky.
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Posted: Tue Nov 13, 2012 7:17 pm Post subject: |
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professional data recovery people hear dd and give up before they start _________________ Now, with penguins, (cuddly such), "contented" means it has either just gotten laid, or it's stuffed on herring. Take it from me, I'm an expert on penguins, those are really the only two options.
--Linus Torvalds |
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Mardok45 n00b

Joined: 21 Jun 2008 Posts: 54 Location: Right behind you
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Posted: Tue Nov 13, 2012 8:40 pm Post subject: |
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| energyman76b wrote: | | MustrumR wrote: | | Code: | | dd if=/dev/urandom of=/dev/sda bs=4K | 4 or 5 times? |
even once is overkill.
FACT: overwriting a disk with ZEROs ONCE is enough. |
If someone has the equipment, they can determine what a certain bit was at some point in time, recovering your data. But if they can afford that kind of equipment, they're probably seeking bigger targets than your porn history. |
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energyman76b Advocate


Joined: 26 Mar 2003 Posts: 2022 Location: Germany
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Posted: Tue Nov 13, 2012 9:10 pm Post subject: |
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| Mardok45 wrote: | | energyman76b wrote: | | MustrumR wrote: | | Code: | | dd if=/dev/urandom of=/dev/sda bs=4K | 4 or 5 times? |
even once is overkill.
FACT: overwriting a disk with ZEROs ONCE is enough. |
If someone has the equipment, they can determine what a certain bit was at some point in time, recovering your data. But if they can afford that kind of equipment, they're probably seeking bigger targets than your porn history. |
no, they can't. Even if they know the state of the bit beforehand they only have a 50% to recover it. Almost everything the pros do is to ignore filesystem errors and scan for data that looks like files. Just like testdisk - just with better equipment.
See also:
http://grot.com/wordpress/?p=154
https://www.anti-forensics.com/disk-wiping-one-pass-is-enough/
http://link.springer.com/chapter/10.1007/978-3-540-89862-7_21 _________________
| AidanJT wrote: |
Libertardian denial of reality is wholly unimpressive and unconvincing, and simply serves to demonstrate what a bunch of delusional fools they all are.
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Satan's got perfectly toned abs and rocks a c-cup. |
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Mardok45 n00b

Joined: 21 Jun 2008 Posts: 54 Location: Right behind you
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Posted: Tue Nov 13, 2012 9:31 pm Post subject: |
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| energyman76b wrote: | | Mardok45 wrote: | | energyman76b wrote: | | MustrumR wrote: | | Code: | | dd if=/dev/urandom of=/dev/sda bs=4K | 4 or 5 times? |
even once is overkill.
FACT: overwriting a disk with ZEROs ONCE is enough. |
If someone has the equipment, they can determine what a certain bit was at some point in time, recovering your data. But if they can afford that kind of equipment, they're probably seeking bigger targets than your porn history. |
no, they can't. Even if they know the state of the bit beforehand they only have a 50% to recover it. Almost everything the pros do is to ignore filesystem errors and scan for data that looks like files. Just like testdisk - just with better equipment.
See also:
http://grot.com/wordpress/?p=154
https://www.anti-forensics.com/disk-wiping-one-pass-is-enough/
http://link.springer.com/chapter/10.1007/978-3-540-89862-7_21 |
That's cool.
If the probability of recovering a bit is 50%, what's the maximum amount of data you can run a MFM scan with a probability of fully recovering the data at, say, 1%? |
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wildhorse Tux's lil' helper


Joined: 16 Mar 2006 Posts: 148 Location: Estados Unidos De América
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Posted: Tue Nov 13, 2012 9:46 pm Post subject: |
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The best way to wipe your personal files is: store them with Microsoft Windows and Microsoft Office.  |
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energyman76b Advocate


Joined: 26 Mar 2003 Posts: 2022 Location: Germany
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Posted: Tue Nov 13, 2012 10:07 pm Post subject: |
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| Mardok45 wrote: | | energyman76b wrote: | | Mardok45 wrote: | | energyman76b wrote: | | MustrumR wrote: | | Code: | | dd if=/dev/urandom of=/dev/sda bs=4K | 4 or 5 times? |
even once is overkill.
FACT: overwriting a disk with ZEROs ONCE is enough. |
If someone has the equipment, they can determine what a certain bit was at some point in time, recovering your data. But if they can afford that kind of equipment, they're probably seeking bigger targets than your porn history. |
no, they can't. Even if they know the state of the bit beforehand they only have a 50% to recover it. Almost everything the pros do is to ignore filesystem errors and scan for data that looks like files. Just like testdisk - just with better equipment.
See also:
http://grot.com/wordpress/?p=154
https://www.anti-forensics.com/disk-wiping-one-pass-is-enough/
http://link.springer.com/chapter/10.1007/978-3-540-89862-7_21 |
That's cool.
If the probability of recovering a bit is 50%, what's the maximum amount of data you can run a MFM scan with a probability of fully recovering the data at, say, 1%? |
3bit? _________________
| AidanJT wrote: |
Libertardian denial of reality is wholly unimpressive and unconvincing, and simply serves to demonstrate what a bunch of delusional fools they all are.
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Satan's got perfectly toned abs and rocks a c-cup. |
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BoneKracker Veteran


Joined: 14 Mar 2006 Posts: 1488 Location: U.S.A.
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Posted: Tue Nov 13, 2012 10:41 pm Post subject: |
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| energyman76b wrote: | | MustrumR wrote: | | Code: | | dd if=/dev/urandom of=/dev/sda bs=4K | 4 or 5 times? |
even once is overkill.
FACT: overwriting a disk with ZEROs ONCE is enough. |
No, it's not. Overwriting it once will protect you from the average data recovery tools, but it won't protect you from forensic-quality analysis.
PFC Manning's personal laptop is a recent case in point. He deleted all his files, reinstalled the OS, reformatted his drive, and then, at somebody's advice, nuked the disk, overwriting it with zero data once (a single-pass wipe). The Army was nevertheless able to recover lots and lots of information from it, including his encryption password, chat logs between Manning and other involved persons, emails he had sent to wikileaks, etc. _________________ Oldthinkers unbellyfeel INGSOC.
-- Headline of a document on Winston Smith's terminal in his cubicle at the Ministry of Truth, seen briefly in the background in one scene of the movie rendition of Nineteen Eighty-Four. |
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energyman76b Advocate


Joined: 26 Mar 2003 Posts: 2022 Location: Germany
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Posted: Tue Nov 13, 2012 10:44 pm Post subject: |
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you might read some of the links I posted. Or google yourself.
Overwritting once defeats even professional tools. _________________
| AidanJT wrote: |
Libertardian denial of reality is wholly unimpressive and unconvincing, and simply serves to demonstrate what a bunch of delusional fools they all are.
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Satan's got perfectly toned abs and rocks a c-cup. |
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BoneKracker Veteran


Joined: 14 Mar 2006 Posts: 1488 Location: U.S.A.
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Posted: Tue Nov 13, 2012 10:46 pm Post subject: |
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| wildhorse wrote: | The best way to wipe your personal files is: store them with Microsoft Windows and Microsoft Office.  |
You can find out all kinds of interesting stuff by opening Word files in a text editor. _________________ Oldthinkers unbellyfeel INGSOC.
-- Headline of a document on Winston Smith's terminal in his cubicle at the Ministry of Truth, seen briefly in the background in one scene of the movie rendition of Nineteen Eighty-Four. |
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BoneKracker Veteran


Joined: 14 Mar 2006 Posts: 1488 Location: U.S.A.
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Posted: Tue Nov 13, 2012 10:46 pm Post subject: |
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| energyman76b wrote: | you might read some of the links I posted. Or google yourself.
Overwritting once defeats even professional tools. |
Sorry, but you're wrong. A single-pass zero-wipe is inadequate protection from the most capable forensic techniques now available. Continue to believe what you want to believe, though. _________________ Oldthinkers unbellyfeel INGSOC.
-- Headline of a document on Winston Smith's terminal in his cubicle at the Ministry of Truth, seen briefly in the background in one scene of the movie rendition of Nineteen Eighty-Four. |
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energyman76b Advocate


Joined: 26 Mar 2003 Posts: 2022 Location: Germany
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Posted: Tue Nov 13, 2012 10:54 pm Post subject: |
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| BoneKracker wrote: | | energyman76b wrote: | you might read some of the links I posted. Or google yourself.
Overwritting once defeats even professional tools. |
Sorry, but you're wrong. A single-pass zero-wipe is inadequate protection from the most capable forensic techniques now available. Continue to believe what you want to believe, though. |
funny that studies and professionals say otherwise....
Ald harddisks from the 80 or early nineties might need more than one pass. Everything else? Nope.
Craig Wright for example is an expert read this please and learn:
http://www.h-online.com/security/news/item/Secure-deletion-a-single-overwrite-will-do-it-739699.html
| Quote: |
a single bit whose precise location is known can in fact be correctly reconstructed with 56 per cent probability (in one of the quoted examples). To recover a byte, however, correct head positioning would have to be precisely repeated eight times, and the probability of that is only 0.97 per cent. Recovering anything beyond a single byte is even less likely.
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| AidanJT wrote: |
Libertardian denial of reality is wholly unimpressive and unconvincing, and simply serves to demonstrate what a bunch of delusional fools they all are.
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Satan's got perfectly toned abs and rocks a c-cup. |
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BoneKracker Veteran


Joined: 14 Mar 2006 Posts: 1488 Location: U.S.A.
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Posted: Tue Nov 13, 2012 11:44 pm Post subject: |
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That's nice. He may be an "expert", but the Manning case this year reveals that the U.S. Army can recover data from single-pass zero-wiped disk.
But unless you're likely to have the determined efforts of a such an organization applied against you, I'd agree that anything more than a single-pass random-data write is overkill.
More often, what screws people is that they've shredded a file, but don't realize that copies of it existed in various other locations, such as tmp files, mail spools, swap space, etc.
As I've said many times before, the only way to really be safe is to use Tin Hat Linux (based on Gentoo Hardened and running entirely in RAM), wait five minutes after shutting down the computer before releasing physical control of it (or yank the RAM), and store any persistent data on a heavily-encrypted USB flash stick which you keep deep in your ass (deeper than the length of a grown man's fingers). _________________ Oldthinkers unbellyfeel INGSOC.
-- Headline of a document on Winston Smith's terminal in his cubicle at the Ministry of Truth, seen briefly in the background in one scene of the movie rendition of Nineteen Eighty-Four. |
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pjp Administrator


Joined: 16 Apr 2002 Posts: 16029 Location: Colorado
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Posted: Wed Nov 14, 2012 1:32 am Post subject: |
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They only have to wait. _________________ lolgov. 'cause where we're going, you don't have civil liberties.
In Loving Memory
1787 - 2008 |
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BoneKracker Veteran


Joined: 14 Mar 2006 Posts: 1488 Location: U.S.A.
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Posted: Wed Nov 14, 2012 1:46 am Post subject: |
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If you're going to keep it in there a long time, you swallow it instead, with a 30-foot-long string, tied to one of your rear molars. Then, when you shit it out, you untie the string from your mouth and pull on it, pulling the flash drive back up into your ass the appropriate distance, tie the string off to your rear molar again, and trim off the excess string in your mouth. When you need it, you just untie the string and wait a few hours.
It's the only way to be sure. If you're really worried enough to be concerned whether you need to overwrite data one vs many times, then you must also be worried enough to this this. _________________ Oldthinkers unbellyfeel INGSOC.
-- Headline of a document on Winston Smith's terminal in his cubicle at the Ministry of Truth, seen briefly in the background in one scene of the movie rendition of Nineteen Eighty-Four. |
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sikpuppy n00b


Joined: 12 Jun 2012 Posts: 23 Location: Central Coast, NSW
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Posted: Wed Nov 14, 2012 6:16 am Post subject: |
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Does the US military still shoot wiped hard drives? That would make it fairly unlikely that the data would ever be recovered, I would imagine. A bolt gun would do the trick as well one would think.
As for recovery after a single pass, that would depend on how sensitive you could make the read of the data. There may still be a magnetic image of the previous data faintly on the platters, but the heads would have to be calibrated differently (in a fashion analogous to the refocussing of the laser on a dual layered DVD).
So, if you are a criminal and you don't want the Man to get you, shoot the crap out of old data and just install a new hard drive. |
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BoneKracker Veteran


Joined: 14 Mar 2006 Posts: 1488 Location: U.S.A.
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Posted: Wed Nov 14, 2012 6:54 am Post subject: |
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I've never heard of anybody shooting disks, except for the fun of it, to see what happens. If I really, really wanted to be ultra-ridiculously safe (like if a disk had the means to wipe out the human race on it), I'd take an arc-welder to the platters.
When I get rid of an old computer, I just use DBAN on the drives, which happens to be on my bootable SystemRescueCD USB flash drive (which is Gentoo-based but not up my ass). It also has some nice tools for low-level disk repair, along with a butt-load (no pun intended) of other utilities. _________________ Oldthinkers unbellyfeel INGSOC.
-- Headline of a document on Winston Smith's terminal in his cubicle at the Ministry of Truth, seen briefly in the background in one scene of the movie rendition of Nineteen Eighty-Four. |
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energyman76b Advocate


Joined: 26 Mar 2003 Posts: 2022 Location: Germany
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Posted: Wed Nov 14, 2012 6:34 pm Post subject: |
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| BoneKracker wrote: | That's nice. He may be an "expert", but the Manning case this year reveals that the U.S. Army can recover data from single-pass zero-wiped disk.
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hm, lets see - from what I gather using google, Manning didn't even really wipe the disk ONCE. He deleted and reinstalled. Oopps. Of course, all the old data structures were there.
Memory cards are a different beast, but this is about hard disks. _________________
| AidanJT wrote: |
Libertardian denial of reality is wholly unimpressive and unconvincing, and simply serves to demonstrate what a bunch of delusional fools they all are.
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Satan's got perfectly toned abs and rocks a c-cup. |
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John R. Graham Administrator


Joined: 08 Mar 2005 Posts: 6443 Location: Somewhere over Atlanta, Georgia
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Posted: Wed Nov 14, 2012 6:41 pm Post subject: |
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This is the longest time I've seen a probable proto-spammer played with without gladiators or Turkish prisons being mentioned.
- John _________________ This space intentionally left blank. |
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