Unix is not as secure as you folks seem to think. A somewhat recent example was the rlogin bug. rlogin is a program that can be executed by any user. However it is suid to root so it assumes root power as it runs. Until recently it loaded the contents of the TERM environment variable into an automatic array without checking to see if it fit. By cleverly setting your TERM variable to a long binary string, a user could deposit machine language code on the stack and then clobber the frame pointer so that the next return statement executed that code. All of this was done with effective uid set to root. And it didn't take the root password or anything like that. The bug was fixed in the late 90's. And HP-UX and SunOS now have kernel options to prohibit executing code on the stack. But I would not bet the rent that there are no more defective suid programs around.