Malware/anti-virus & Email security

Another, DON'T.

There are no Mac viruses. None. There's nothing for AV software to look for. There are plenty of Trojans, which is any type of malware that requires the USER to do something that allows it to get installed. No AV software will make even the slightest attempt to stop you from doing so. AV software is utterly useless.

Scammers spoof emails addresses all the time. There's no AV software in the world which can prevent that since it has nothing to do with your computer to begin with. My business email got suspended for a short time because scammers had seriously abused it for their garbage. Once blacklisted, they immediately move on to someone else's address. I had to go through a few verification steps to get my address cleared again.

She can either create a new email account, or try to get her account cleared. Start here if she prefers the latter.

cdale wrote:

Thank you for sharing. I think I will print it out and give to Mom. Sometimes she clicks on things she shouldn't, thinking they're legitimate, and unfortunately I don't live near to fix things as often as she would like.

Three things you can do:

(1) Set her up as a standard user, not administrator. This will not prevent everything but will help prevent some.

(2) Instruct her NEVER to click on any link in an email without first contacting you, e.g. describing it on the phone or forwarding the email to you first. Kind of tedious but maybe will help "train" her.

(3) Have your sister insert a custom signature (it could just be one word, or show a middle initial) for her legitimate emails. If an email is received "from her" that doesn't have that, whoever gets it will be alerted that it could be an imposter.

(0) Get Time Machine configured and running. if you have the budget for it, via NAS with Time Machine support. That NAS gets the backup located further away from the computer. Out of coffee spill range, etc. Otherwise, via locally-connected hard disk storage. Probably 4 to 6 TB, or so.

... {good list, above} ...

(4) Set up mail rules that automatically file all arriving messages with attachments from any unrecognized mail senders as spam. I’d consider setting all mail from unrecognized senders to be treated as spam; for all arriving mail, save for that mail either with addresses in the address book, or previously emailed.

(5) Set up your own admin login, with your own password. This as a means of access if the main accounts are somehow blocked.

(6) Get iCloud Keychain configured for password storage. Because passwords get forgotten. And because iCloud Keychain won’t enter credentials into phishing websites.

(7) In Safari, disable automatically opening of “safe” attachments.

DON’T.

Read this post by one of the most respected members of this community, about keeping your mac safe:

https://discussions.apple.com/docs/DOC-8841

+1 to Luis Sequeira1's response. DON'T install any.

here's the page he tried to give you the link for: Effective defenses against malware and other threats - Apple Community

Here’s some info on what one of the better-known Mac anti-malware packages implemented:

https://www.vice.com/en/article/qjdkq7/avast-antivirus-sells-user-browsing-data-investigation