~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	OFF BY ONE vuln
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

It happens when the coder incorrectly sets the limits of an array

  for (i=0; i<5; i++)   -> loops 5 times
  for (i=0; i<=5; i++)   -> loops 6 times  <- off by one error

FencePost error:
If you build a fence 100 feet long with posts 10 feet apart, 
how many posts do you need?
10?? WRONG!   <- Off by one error
11   <-- YES

strncat() vuln code:
-----------------------------------------------------------------------------
int foo (char *s) {
    char buf[15];
    memset(buf, 0, sizeof(buf));
    strncat(buf, s, sizeof(buf)); // Final parameter should be: sizeof(buf)-1
    return(0);
}
-----------------------------------------------------------------------------

On some systems (little endian architectures in particular) this can result 
in the overwriting of the least significant byte of the *frame pointer*. This 
can cause an exploitable condition where an attacker can hijack the local 
variables for the calling routine.

Rsrc: wikipedia