Security and $PATH

[van at sequel.UUCP]

The discussion of whether to allow '.' in the $PATH reminds me of an
incident that occurred where I used to work.  When we first got our VAX/UNIX
system up one of the people in charge of the system wrote two utilities
which he called au (add user) and du (delete user) and which were very
useful for doing those jobs.  He placed these in the /etc directory.
About 3 months later the other system administrator was trying to determine
how much disk space was used by a certain user.  So he typed
'du /user/user_name', unfortunately he was in /etc at the time and '.' was
the first entry in his $PATH.  When du didn't print the expected data on
the screen he scratched his head and typed 'du /user/*', fortunately a
few seconds into this he aborted the command.  By that time though he had
removed 4 users and their entire directory structures and partially removed a
fifth (me).

Needless to say du was quickly renamed 'removeuser' and the administrator
paid the price by having to spend a couple of days restoring all our
files from backup tapes.

I hope that this illustrates the problem of having '.' at the start of your
$PATH and the problem of not choosing resonable names for dangerous utilities.
-- 

John Vander Borght ...pur-ee!sequel!van