Securely Delete files from Journaling Filesystems in Ubuntu and Linux Operating Systems
Previously I posted a tutorial on setting up wipe with Nautilus, It has come to my attention that since ext3 is a journaling file system that wipe isn't enough to securely delete files from people that have the tools/hardware to recover files, today I will show you how to delete a file that is unrecoverable to the best of my knowledge.. Read on if you like :)
WARNING: DO NOT RUN THESE POSIX COMMANDS UNLESS YOU ARE EXTREMELY CAREFUL
Issue these commands carefullydd if=/dev/zero of="file you want shreded"
sync
shred -u -v -n 5 "file you want shreded"
sync
Breaking it down, the commands say this:
* dd: "move data around"
* if=: "the input file is..."
* /dev/zero: "not a file at all, but a device that outputs an unending stream of zeros"
* of=: "and the output file is..."
* sync writes any data buffered in memory out to disk. This can include (but is not limited to) modified super blocks, modified inodes, and delayed reads and writes. This must be implemented by the kernel; The sync program does nothing but exercise the sync(2) system call.
* shred Overwrites the specified FILE(s) repeatedly, in order to make it harder for even very expensive hardware probing to recover the data.
If you have any other suggestions please share your knowledge, security & privacy should be common knowledge in todays world
defcon
