"The contemporary method of /dev/null drivers is described as the "high
suction algorithm" in comparison with the replacement that vendors have
made available for their systems. If a malicious user uses a program
with low-resistance logic to connect /dev/null back into itself,
the device goes critical and can be used for destructive purposes.
"Once the /dev/null device driver enters a critical state, programs with
low-resistance logic will break, be consumed by /dev/null and expose
their standard input to the full force of /dev/null itself. Some examples
which have been verified in labs include the following:
* Programs which are consumed by /dev/null become permanent entry points
to /dev/null afterward.
* If standard input is redirected from any regular file, it will be
"sucked dry" and left empty. File permissions do not prevent loss
of data.
* If standard input is redirected from a directory, all the files and
directories within it will be sucked dry, recusrively removing an
entire directory tree."
