internet security help please

The computer certainly isn't causing any fraud, perhaps it's some of the sites that they have used.

 

It's possible they fell for a phishing scam, but it would be very hard to track down any specific sites. I'd recommend they get smart on computer security and internet safety. There's tutorials online to do some of this. With people new to the internet it's hard to get everything across to them.

Also, if they same credit cards are targeted, I would get new ones as once the hackers have it, they'll continue to attack it.

 

I don't know if that helps, but have a look at Activity Monitor ( Applications / Utilities / ) and select All Processes and sort by Process Name to see what the culprit may be.

image below uses sorting by CPU as an example


Then press CMD+A to select all processes, CMD+C to copy them to the clipboard, and paste the clipboard into your next post via CMD+V.

 

It's also possible they chose weak passwords for some account, or used the same (possibly weak) passwords for multiple accounts.

Or it's possible that one or more of the vendors they used a credit card at has been breached.

Or even a credit card skimmer at a store or gas station.

Really, there are any number of ways for credit card numbers to be compromised, and without a lot more details, and possibly some kind of non-trivial forensics, it's unlikely to be able to tell exactly what the cause is.


One way to tell if a particular site is a problem is to use one card, and only one card, at that site, and don't use that card at any other site. If the card is compromised, it's a pretty good indicator it's that site. Not 100% certain, because there are other avenues of attack, but they are far less likely than a compromised site.

 

On you parent's Mac mini (or netter their internet router) start using OpenDNS.com. If you sign up for a free account you can block known phishing (the OpenDNS service using PhishTank to block sites, if you tell it to). The OpenDNS has an instructional video to show how using their site can help you.

Plus it sounds as if your parents might have fallen victim to internet hijinks. This would have happen even from PCs. If fraudulent charges are appearing have you parents contact the banks that issued the cards and have then change the numbers, because it sounds as if the numbers have been stolen. I know this will be a pain but it is the safest thing your parents can do to make sure they are safe. Then sit them down and tell them the pitfalls of internet scams and how to have a critical eye for things on the internet & email. The old saying of 'to good to be true' rings more true on the internet today than ever before.