Thanks for the quick reply Richard. We are trying to figure out how he obtained the API Transaction Key and password and we are not exactly sure which 1 of our IT guys did it. We know it came from within because only an IT User would have access to some of the information to process cards. We have already changed the keys and are going to start using Tokens instead of the Credit Cards, which I recommended to CTO years ago, but why listen to me then :)
Unfortunately hacking is a little above my pay scale :) We have had this site up for 7 or 8 years and I have never seen anything like this before. Trying to figure out if we are passing information to auth.net that is not using HTTPS protocols now.
Do you happen to know of any links that would help my analysis on how he might have done it? I have look at WireShark and Fiddler, but not sure those will work using HTTPS.
Thanks again for your help.