"Question about the gets() function in C" as a security threat

buffer overruns:

These are a great way to get to root (superuser) in unix.
This will let you install a rootkit and commit other atrocities. Buffer overruns are a major security hole in unix. 'nuff said as guys like our friend bin Laden and his hacker cronies could be watching....

Paranoia is fun, if you're only slightly insane.
Otherwise it ruins your whole day.

If you can't tell, I think unix needs thoracic surgery, but the keepers of the keys think otherwise.

Yes, but stack smashing is bloody hard unless you know the EXACT revision (as in, not just version, what the file was compiled as) and even then it's tricky.