This Quora
article by Eddie Offermann made 'The HDD drilling scene' crystal clear for me
Copying the article for archiving
- It does the most damage to data recovery in the least possible amount of time, barring
access to more thorough mechanical and electromagnetic methods of
data remanence.
-
A secure reformat (minimum 3x overwrite of the entire drive surface - and depending on
who wants your data, you might consider doing it more)
is extremely time-consuming. If you have a great many hours to spare, AND you want to
save the drives for reuse, repetitively overwriting
the drive surface is adequate for "normal" people. It will prevent most basic efforts at
data recovery and is probably fine unless
you think you're about to be raided by people intent on recovering your data. It's not
foolproof though - there have been processes for decades
that can determine what erased bitstates were on a piece of media for the longest amount
of time. Those subsequent overwrites were only
there for a brief moment, and magnetic media has something of a "settling time". Some of
the old data will remain, just smaller
amounts of it than the drive is designed to detect, and it can be recovered using
specialized techniques.
-
Physical destruction of the device (drilling holes in the drive or even running it
through a large commercial shredder) isn't 100% either -
government agencies and commercial enterprises have processes to recover data from small
fragments of drive platters. It won't be like dragging a
file back out of the trash - it's a time-consuming process that typically yields small
fragments of files - but it means your data still
comes back to life. If the data is worth subjectively more than the cost of recovery, at
least some of it will be recovered by a dedicated party.
-
The NSA recommends Degaussing
magnetic media using an NSA-approved device appropriate to the Coercivity of the drive
you're erasing - AND that this be followed by physical destruction of the media. Neither
is considered entirely sufficient
on its own, at least in part because while you may be certain that 99.9% of the data is
destroyed, that .1% might still be incredibly damaging.
You don't get to pick which parts remain recoverable - so you have to try as hard as you
can to ensure it's ALL gone.
-
If Elliot had been more prepared, he'd have had a degausser handy - but I've only known
one hacker who kept one around. This was in the olden days,
back in the 1980s, but this friend kept his removable media in a box with a degausser
(powered by a car battery and inverter)
and had panic switches in a couple of places in his house to start it. That's not quite the
recommended way of degaussing media, but it gave him a certain
degree of confidence that if his door was kicked in or the FBI came knocking, he
could press the button and possibly erase a considerable amount of data.
In his eyes, it was better than the alternative and that was probably correct. (There
are a whole separate set of legal issues involved in the willful
destruction of evidence - but it's not always about hiding evidence. If you're
blackhatting commercially, other unsavoury characters that
want your data and if they know they can't just barge in and take it, they might be less
likely to try.)
-
I don't think degaussing has ever been broadly popular in blackhat circles - it's more
of a process that gets used in secure facilities than a device that
individuals use. It's just too cumbersome and you rarely have sufficient warning to use
it in an emergency.
Drilling some holes in your drives and running like hell is probably as good as it gets,
and that's what Elliot did."