Data protection needs require different levels of destruction. Scott Lowe covers four methods that might be considered ineffective for particularly high security needs.
My previous TechRepublic blog covered five ways to accomplish your data destruction goals when destroying magnetic media. Some of the proposed methods are extreme but serve the overarching data protection goal. I think it's important to also point out methods that don't always meet the standard when it comes to data protection.
1: Deleting a file or email message
A user makes the ultimate and seemingly final decision to delete a file or an email message. Once that Delete key is hit, the data will be gone forever, right? It's actually extremely easy to recover a file or other item that has simply been deleted.
At one organization where I worked, a termination was handled poorly, and the person was allowed to go back to his office unaccompanied to clean up his files. He ran through his hard drive and deleted a bunch of files, and then opened Outlook and deleted all of his email messages. Later that day, his supervisor called me in a panic indicating that all of this information had been deleted. I was able to recover the data by remotely connecting to the machine, recovering the deleted files from the Recycle Bin (yes, the Recycle Bin), and then opening Outlook and undeleting the messages. The recovery process took about two minutes, and all of the information was back where it needed to be.
2: Formatting a disk
Let's take the solution to the next level and actively format the hard drive as a means to wipe the disk back to an empty state. Although that is the case, recovering information from a formatted hard drive is as simple as buying the $79 program GetDataBack for NTFS and running it against the formatted hard drive. Here's an excerpt of a user's review of GetDataBack for NTFS:
"It was the only program I've tested that was able to able to restore not only the content of all files, but the correct filenames as well. Within one hour it scanned the whole hard drive of 120 GB for all its structure, data and lost files. As result it showed me a 'tree' of all the lost data, like in the Windows Explorer. Everything has been there, nothing has been missing. I was prompted to mark all the data I wished to save and make the program copy it to a 'healthy' partition. Thanks to GetDataBack for NTFS I've got all my lost data back, with no single error!"
As you can tell from this review, it's not exactly rocket science to recover information from a formatted disk.
3: Drilling holes in a drive
I've read recommendations that users should drill multiple holes all the way through a hard drive -- the metal casing and the platters -- as a means to protecting the data on a drive. This method will make it extremely difficult to use recovery tools for particularly sensitive information, but drilling the drive isn't even enough to declare victory.
Think of your hard drive as a donut. Now, imagine using a pencil to poke a bunch of holes in the donut to simulate drilling through a drive. Even if you have a bunch of little holes in the donut, you still have the donut's critical mass, and you can pick it up and chomp away. If we extend this analogy to a hard drive, although you will make it impossible to access certain areas of this disk (i.e., the holes), the rest of the platter(s) remain susceptible to prying eyes. All of that platter space may remain accessible by anyone who is desperate enough for the information.
4: Hammering a drive
When you want to destroy a drive, a hammer may not always do the job -- unless you take it to an extreme. You would need to smash the drive to such an extent that it couldn't be placed back into a computer, and the individual platters couldn't be reasonably salvaged.
In a one-off situation, a sledgehammer might be feasible if you have to destroy dozens of drives; otherwise, the other destruction types I mentioned in my previous TechRepublic blog might be better options. Of course, there could be something therapeutic about smashing old hardware to smithereens, but most IT pros have better things to do with their time.