[vox-tech] Secure Wiping hard drives
We need a fast way to securely wipe hard drives. Is there really any way to recover data after doing 1 pass writing zeros to every sector? (This is what we are doing now using the free version of Active Killbits, but it takes over an hour per hard drive.) If we repartition and reformat Windows NTFS drives as Ext3, is there any way to recover data from them? (We found this method is faster, but are not sure if it is as secure as the above.) The company will not pay for a degausser. Safety requirements prevent us from doing physical destruction of the sledge-o-matic variety. We use a computer recycler, but do not trust them 100% to destroy our data. We know for a fact that equipment they get from us sit unguarded in a warehouse for months before destruction. Interested in hearing opinions on this. ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech
Re: [vox-tech] Secure Wiping hard drives
On 05/11/2012 09:32 AM, Darth Borehd wrote: We need a fast way to securely wipe hard drives. Is there really any way to recover data after doing 1 pass writing zeros to every sector? (This is what we are doing now using the free version of Active Killbits, but it takes over an hour per hard drive.) If we repartition and reformat Windows NTFS drives as Ext3, is there any way to recover data from them? (We found this method is faster, but are not sure if it is as secure as the above.) The company will not pay for a degausser. Safety requirements prevent us from doing physical destruction of the sledge-o-matic variety. We use a computer recycler, but do not trust them 100% to destroy our data. We know for a fact that equipment they get from us sit unguarded in a warehouse for months before destruction. Interested in hearing opinions on this. Maybe using dd would be faster, since you can do it from DSL linux or some other tiny bootable linux on a usb stick. Though if it has to write a bit to every sector of course it's going to take a while. The cool part here is you can do more than 1 drive at a time (if the drives are being taken out of machines and connected to the wiping machine). dd if=/dev/zero of=/dev/sda My non CS understanding is you should 0 everything, other stuff obscures the data but doesn't remove it. So depending on the tools and how crafty a thief is something is recoverable. I'm sure someone else here has much more to say/explain/suggest. Enjoy, Alex ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech
Re: [vox-tech] Secure Wiping hard drives
DBAN looks like it will do what you want: http://www.dban.org/ But you can't securely erase a drive without writing to every sector, and that will take time. More challenging is how to securely dispose of a defective drive. I'd use a sledgehammer. Do a cost analysis and maybe a solution for the safety requirements will magically appear. :) Rod On 05/11/2012 09:32 AM, Darth Borehd wrote: We need a fast way to securely wipe hard drives. Is there really any way to recover data after doing 1 pass writing zeros to every sector? (This is what we are doing now using the free version of Active Killbits, but it takes over an hour per hard drive.) If we repartition and reformat Windows NTFS drives as Ext3, is there any way to recover data from them? (We found this method is faster, but are not sure if it is as secure as the above.) The company will not pay for a degausser. Safety requirements prevent us from doing physical destruction of the sledge-o-matic variety. We use a computer recycler, but do not trust them 100% to destroy our data. We know for a fact that equipment they get from us sit unguarded in a warehouse for months before destruction. Interested in hearing opinions on this. ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech
Re: [vox-tech] Secure Wiping hard drives
Quoting Darth Borehd (darth.bor...@gmail.com): We need a fast way to securely wipe hard drives. _How_ secure? LLNL actually melts the platters on hard drives retired from their security-sensitive computing vaults. Commercial operations generally consider DBAN good enough. ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech
Re: [vox-tech] Secure Wiping hard drives
How secure is a single pass zero-fill? As secure as that. On 11 May 2012 10:25, Rick Moen r...@linuxmafia.com wrote: Quoting Darth Borehd (darth.bor...@gmail.com): We need a fast way to securely wipe hard drives. _How_ secure? LLNL actually melts the platters on hard drives retired from their security-sensitive computing vaults. Commercial operations generally consider DBAN good enough. ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech
Re: [vox-tech] Secure Wiping hard drives
I second DBAN. Writing zeros may seem effective and probably can be in certain cases, but if you think about it, all those zeros could easily be represented in one small portion and the remainder be the old data. There is no way to store random data in a caching mechanism, so it would have to clear the drive. You might also consider scrub. It is maintained by Jim Garlick at LLNL. http://code.google.com/p/diskscrub/ On Fri, May 11, 2012 at 10:21:18AM -0700, Rod Roark wrote: DBAN looks like it will do what you want: http://www.dban.org/ But you can't securely erase a drive without writing to every sector, and that will take time. More challenging is how to securely dispose of a defective drive. I'd use a sledgehammer. Do a cost analysis and maybe a solution for the safety requirements will magically appear. :) Rod On 05/11/2012 09:32 AM, Darth Borehd wrote: We need a fast way to securely wipe hard drives. Is there really any way to recover data after doing 1 pass writing zeros to every sector? (This is what we are doing now using the free version of Active Killbits, but it takes over an hour per hard drive.) If we repartition and reformat Windows NTFS drives as Ext3, is there any way to recover data from them? (We found this method is faster, but are not sure if it is as secure as the above.) The company will not pay for a degausser. Safety requirements prevent us from doing physical destruction of the sledge-o-matic variety. We use a computer recycler, but do not trust them 100% to destroy our data. We know for a fact that equipment they get from us sit unguarded in a warehouse for months before destruction. Interested in hearing opinions on this. ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech -- Brian Lavender http://www.brie.com/brian/ There are two ways of constructing a software design. One way is to make it so simple that there are obviously no deficiencies. And the other way is to make it so complicated that there are no obvious deficiencies. Professor C. A. R. Hoare The 1980 Turing award lecture ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech
Re: [vox-tech] Secure Wiping hard drives
On 05/11/2012 10:21 AM, Rod Roark wrote: DBAN looks like it will do what you want: http://www.dban.org/ There is also the program 'scrub' which can do a full secure wipe of the drive. Tony ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech
Re: [vox-tech] Secure Wiping hard drives
I believe shred could also do the job. shred -u -z On May 11, 2012 11:14 AM, Tony Cratz cr...@hematite.com wrote: On 05/11/2012 10:21 AM, Rod Roark wrote: DBAN looks like it will do what you want: http://www.dban.org/ There is also the program 'scrub' which can do a full secure wipe of the drive. Tony ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech
Re: [vox-tech] Secure Wiping hard drives
Repartitioning will do very little; though it certainly makes the files seem to disappear, data recovery software can still find the individual ones and zeroes and read them as raw files (no metadata like filenames, but the data itself is still there). So yeah, using the dd command or a dedicated utility that actually clears the data bit-by-bit is your best bet in terms of absolute security. It'll take awhile, but it's vastly more reliable and effective. For added fun you could dd textual data onto a drive (like nice try, punk!) by using the dd command and specifying a text file with your desired message as the input. Hope that all helps. - Ryan Northrup On May 11, 2012 9:41 AM, Darth Borehd darth.bor...@gmail.com wrote: We need a fast way to securely wipe hard drives. Is there really any way to recover data after doing 1 pass writing zeros to every sector? (This is what we are doing now using the free version of Active Killbits, but it takes over an hour per hard drive.) If we repartition and reformat Windows NTFS drives as Ext3, is there any way to recover data from them? (We found this method is faster, but are not sure if it is as secure as the above.) The company will not pay for a degausser. Safety requirements prevent us from doing physical destruction of the sledge-o-matic variety. We use a computer recycler, but do not trust them 100% to destroy our data. We know for a fact that equipment they get from us sit unguarded in a warehouse for months before destruction. Interested in hearing opinions on this. ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech
Re: [vox-tech] Secure Wiping hard drives
Hi guy. Next week is Sac State finals week ,,, things are slowing down. Question: To my knowledge my machine has not had an automatic update since your last session. Is it doing it without my knowledge (I don't mind) or is it totally turned off? If so, is this bad? Denny --- On Fri, 5/11/12, Eric Lin notapplicable.h...@gmail.com wrote: From: Eric Lin notapplicable.h...@gmail.com Subject: Re: [vox-tech] Secure Wiping hard drives To: lugod's technical discussion forum vox-tech@lists.lugod.org Date: Friday, May 11, 2012, 12:44 PM I believe shred could also do the job. shred -u -z On May 11, 2012 11:14 AM, Tony Cratz cr...@hematite.com wrote: On 05/11/2012 10:21 AM, Rod Roark wrote: DBAN looks like it will do what you want: http://www.dban.org/ There is also the program 'scrub' which can do a full secure wipe of the drive. Tony ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech -Inline Attachment Follows- ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech
Re: [vox-tech] [Lug-nuts] Secure Wiping hard drives
Anything requiring power tools, sledgehammers, drills, or small bits flying off is vetoed by the company HR due to safety. Shotgun is *WAY* out. (Except for maybe the Texas office). Vinegar? Would that really work? I imagine HR would say no the hydrogen waste gas too, if not the smell would disrupt the office workers in the next room. DBAN takes 2 to 3 hours but is thorough. And it looks like repartitioning is about as secure as putting a yellow sticker on it that says erased. :/ On 11 May 2012 13:54, Mikies Runs Baal mikiesrunsbaal@sbcglobal.netwrote: Government standards for a security wipe is a rewrite done 7 times. Many manufacturers have a Low-Level Format utility that can be used. However, some intelligent drives actually block a LLF, but FALSELY report as completed! Dismantling a drive only requires a reassemble to regain access to any recoverable data. The hammer or shotgun technique does not destroy data. So, any chunks large enough can be used to recover partial files. Since, data platters are made of metallic alloys like aluminum, they are highly susceptible to irrecoverable damage by acids. Drill multiple holes in the drive case, and drop in a bucket of vinegar, and forget. BTW, no smoking. This method generates lots of hydrogen gas which s highly explosive. Best to use in area with lots of ventilation. IMHO, MJR On 5/11/2012 9:32 AM, Darth Borehd wrote: We need a fast way to securely wipe hard drives. Is there really any way to recover data after doing 1 pass writing zeros to every sector? (This is what we are doing now using the free version of Active Killbits, but it takes over an hour per hard drive.) If we repartition and reformat Windows NTFS drives as Ext3, is there any way to recover data from them? (We found this method is faster, but are not sure if it is as secure as the above.) The company will not pay for a degausser. Safety requirements prevent us from doing physical destruction of the sledge-o-matic variety. We use a computer recycler, but do not trust them 100% to destroy our data. We know for a fact that equipment they get from us sit unguarded in a warehouse for months before destruction. Interested in hearing opinions on this. ___ Lug-nuts mailing listLug-nuts@saclug.orghttp://www.leibmanland.com/cgi-bin/mailman/listinfo/lug-nuts ___ Lug-nuts mailing list lug-n...@saclug.org http://www.leibmanland.com/cgi-bin/mailman/listinfo/lug-nuts ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech
Re: [vox-tech] Secure Wiping hard drives
Reply to author perhaps? On Fri, May 11, 2012 at 02:42:49PM -0700, Dr. Denny Scronek wrote: Hi guy. Next week is Sac State finals week ,,, things are slowing down. -- Brian Lavender http://www.brie.com/brian/ There are two ways of constructing a software design. One way is to make it so simple that there are obviously no deficiencies. And the other way is to make it so complicated that there are no obvious deficiencies. Professor C. A. R. Hoare The 1980 Turing award lecture ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech
Re: [vox-tech] Secure Wiping hard drives
On Fri, May 11, 2012 at 10:25:02AM -0700, Rick Moen wrote: Quoting Darth Borehd (darth.bor...@gmail.com): We need a fast way to securely wipe hard drives. _How_ secure? LLNL actually melts the platters on hard drives retired from their security-sensitive computing vaults. I would think that writing zeros to the disk would make the data unavailable in many cases and is relatively fast. IIRC, DBAN takes multiple passes with pseudorandom data. What if the fact that a melted disk leaked information? One could not even consider that secure. Similar if the NSA orders pizza delivered. Personally, I would go one step further and use a pseudo random feed from AES with Cipher Block Chaining (CBC) and perhaps throw some salt in the middle so that it isn't too predictable. You might be able to do this with DBAN with a one sweep pass. Commercial operations generally consider DBAN good enough. -- Brian Lavender http://www.brie.com/brian/ There are two ways of constructing a software design. One way is to make it so simple that there are obviously no deficiencies. And the other way is to make it so complicated that there are no obvious deficiencies. Professor C. A. R. Hoare The 1980 Turing award lecture ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech
Re: [vox-tech] [Lug-nuts] Secure Wiping hard drives
On Fri, May 11, 2012 at 3:00 PM, Darth Borehd darth.bor...@gmail.com wrote: Anything requiring power tools, sledgehammers, drills, or small bits flying off is vetoed by the company HR due to safety. Shotgun is *WAY* out. (Except for maybe the Texas office). Would they allow running trucks over hard drives? Eric ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech
Re: [vox-tech] [Lug-nuts] Secure Wiping hard drives
On Fri, May 11, 2012 at 03:20:40PM -0700, Eric Lin wrote: On Fri, May 11, 2012 at 3:00 PM, Darth Borehd darth.bor...@gmail.com wrote: Anything requiring power tools, sledgehammers, drills, or small bits flying off is vetoed by the company HR due to safety. Shotgun is *WAY* out. (Except for maybe the Texas office). Would they allow running trucks over hard drives? How easy is it to get at data that was zeroed out using dd from /dev/zero? brian -- Brian Lavender http://www.brie.com/brian/ There are two ways of constructing a software design. One way is to make it so simple that there are obviously no deficiencies. And the other way is to make it so complicated that there are no obvious deficiencies. Professor C. A. R. Hoare The 1980 Turing award lecture ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech
Re: [vox-tech] Secure Wiping hard drives
Zeroing out all bytes gives some level of security, but is not enough against a truly determined adversary who has lots of resources, according to what I've read. A disk drive, being a mechanical device, will write to a slightly different physical spot each time it writes to a particular bit position on the disk. Sophisticated sensing mechanisms may thus be able to determine what had been stored in that bit before a 0 was written to it. For that reason, the more sophisticated shredding utilities do more than merely write 0s; they will do so multiple times. Norm Matloff ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech
Re: [vox-tech] Secure Wiping hard drives
There are a bunch of secure delete programs that one-up dd by overwriting the file many times, asking the OS to sync the changes to disk immediately, etc. srm, wipe, shred and diskscrub documentation all reference a paper by Peter Gutmann: Secure Deletion of Data from Magnetic and Solid-State Memory (http://static.usenix.org/publications/library/proceedings/sec96/full_papers/gutmann/). wipe (http://lambda-diode.com/software/wipe) seems to overwrite the disk 34 times with different bit patterns. srm defaults to 35 passes. Harold On Fri, May 11, 2012 at 4:07 PM, Brian Lavender br...@brie.com wrote: Perhaps dd from /dev/zero is the solution for this problem? Wikipedia makes reference to a SpringerLink publication. See below for both. http://en.wikipedia.org/wiki/Dd_%28Unix%29#Disk_wipe Wright, Craig; Dave Kleiman2, and Shyaam Sundhar R.S. (2008). Overwriting Hard Drive Data: The Great Wiping Controversy. Lecture Notes in Computer Science. Information Systems Security 5352: 243.257. doi:10.1007/978-3-540-89862-7_21. Retrieved 7 March 2012. On Fri, May 11, 2012 at 03:47:39PM -0700, Norm Matloff wrote: Zeroing out all bytes gives some level of security, but is not enough against a truly determined adversary who has lots of resources, according to what I've read. A disk drive, being a mechanical device, will write to a slightly different physical spot each time it writes to a particular bit position on the disk. Sophisticated sensing mechanisms may thus be able to determine what had been stored in that bit before a 0 was written to it. For that reason, the more sophisticated shredding utilities do more than merely write 0s; they will do so multiple times. Norm Matloff ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech -- Brian Lavender http://www.brie.com/brian/ There are two ways of constructing a software design. One way is to make it so simple that there are obviously no deficiencies. And the other way is to make it so complicated that there are no obvious deficiencies. Professor C. A. R. Hoare The 1980 Turing award lecture ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech
Re: [vox-tech] Secure Wiping hard drives
On 05/11/2012 09:32 AM, Darth Borehd wrote: We need a fast way to securely wipe hard drives. As you might imagine the faster the less secure. Are you trying to protect against: * A determined attacker with a $10M budget? * An expert willing to do disk surgery? * Someone that wants 99% of the drive? * Someone that wants even just a few 100 bits? * Joe Random running some undelete/recovery tool? The knee in the curve is to use the ATA Secure Erase or a single pass random overwrite. Is there really any way to recover data after doing 1 pass writing zeros to every sector? (This is what we are doing now using the free version of Active Killbits, but it takes over an hour per hard drive.) Yeah, zillions of ways to do that. Linux dd will happily do this as well. Keep in mind that an overwrite will NOT overwrite any sectors marked bad. Secure erase should make it much harder to read those sectors marked bad. The only secure way to instantly securely erase a drive are physical means (destruction) or to use a strong password in the first place (and make sure the attacker doesn't have said password). If we repartition and reformat Windows NTFS drives as Ext3, is there any way to recover data from them? (We found this method is faster, but are not sure if it is as secure as the above.) Yeah, that's will stop only the most casual of attacks. Someone even moderately curious about the used computer/drive they bought used might well run a partition/file recovery tool and easily get close to 100% of your data back. The company will not pay for a degausser. Safety requirements prevent us from doing physical destruction of the sledge-o-matic variety. We use a computer recycler, but do not trust them 100% to destroy our data. We know for a fact that equipment they get from us sit unguarded in a warehouse for months before destruction. Within your constraints I think you already have the best solution. Interested in hearing opinions on this. Keep in mind that Peter Gutmann did design a series of 35 patterns for overwriting, but he also does NOT advocate overwriting 35 times. A quote: In the time since this paper was published, some people have treated the 35-pass overwrite technique described in it more as a kind of voodoo incantation to banish evil spirits than the result of a technical analysis of drive encoding techniques. As a result, they advocate applying the voodoo to PRML and EPRML drives even though it will have no more effect than a simple scrubbing with random data. So while theoretically someone could recover some bits from a drive overwritten once, the labor required to make a VERY high resolution magnetic image (this takes a LONG time on a very expensive machine) it's not a practical attack. Someone's more likely to throw large bundles of cash at your janitor before attempting such extreme measures. So in cases where serious cases of espionage at the corporate of government level physical destruction is the standard. But if you are just trying to protect the random personal information a single overwrite should be plenty. Granted random numbers (or pseudo random) is likely to be somewhat better that zeros. ___ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech
