Hacked with "malicious software"?

I received the same email yesterday. And I should admit that at first, it felt terrible. Happily, when I searched more about this incident I found that it is most likely a scam that aims to blackmail its victims into paying a ransom fee. Since I was not sure if my machine is secure enough, I run a scan with anti-malware tool. It detected several other minor issues but no Trojan or severe malware was present on it.

No. they lied. They probably did get your password and email address from a web site that was compromised at some point in the past... but they have not hacked your machine.

To be successful, the "hacker" would have to have access to your home router and your iMac.

By default, most consumer-grade routers are enabled with a NAT firewall. This is not a true firewall, but can still be effective in preventing unsolicited traffic from entering your home's network. Routers that come with built-in firewall features, such as Stateful Packet Inspection (SPI) or Intrusion Prevention System (IPS), would be much more effective for this purpose. Also, if security is critical to you, a dedicated hardware firewall appliance could be used "in front" of the router ... especially if you have a very simple router which doesn't include any real firewall functions ... like the Apple routers.

Also, your iMac comes with two built-in software firewalls. Application-level and network-level. Both are disabled by default. Again, whether or not, you enable either or both is really up to you on how "secure" you want your Mac to be. However, realize any firewall (hardware or software) will take its toll on throughput performance.

I second dialabrain's comments ... it's SPAM.

• Phishing & Other Suspicious Emails - Apple Support
• Avoid phishing emails, fake 'virus' alerts, phony support calls, and other scams - Apple Support

It's a scam. You and your Mac is fine.

Just in case you have any doubts, I agree it is spam.

You're welcome.

What software did you use to do the scan?

Some of them are worst then the problem they claim they will solve for you.