Martin Soto wrote:
Not quite. A hacker owning your account could at most do something like 'rm -rf ~/*'. This is really bad, but you could at least have something like an unerase mechanism in place at the filesystem level (if such a thing is currently available for the existing linux filesystems is another story, but I guess my argument still holds). If the hacker has root access he can do a 'dd if=/dev/random of=/dev/hda' and then there's no unerase that helps.
Not true. If I'm a hacker with access to your account, it isn't hard to destroy all your user's data so that you can't get it back.
Just delete ~/, then run df to see how much space is available, and then create a file of that size filled with random bits, and delete and recreate it 10 times (it takes about 10 re-writes of random bits to destroy data beyond recovery on a hard disk).
There's absolutely no advantage here to having "dd" available.