Regsub always returns a 1 never 0

Oh, I forgot to add that if you want to scrub the CC, then you'll likely want to change the regexp to --indices which will return a list of the start, end index of each match. You can then use string range to extract each card num for validation but then use the indices with the command "HTTP::payload replace " to scrub out the card number (replacing just sections of the payload is going to be more efficient than replacing the entire thing with a modified $payload variable).