First, if you want to do a quick check for malware, the free version of Malwarebytes is a good utility.
Next, I think what you do on an ongoing basis depends on how you use your computer. Some things that would lead me to install an anti-virus package include:
- Sending or receiving files with Windows users
- Regular downloading of file types that often are virus vectors, such as .pdf, .jpg, .doc, and .xls .
- Any business use of your machine
- Frequent use of public Wi-Fi networks
I've used Sophos for many years. While I can't recall it ever finding a virus, the web address filtering function has saved me from potentially dangerous URL typos and search engine clicks many times.
If you're dead set against installing anti-virus software, you can at least run downloads you think are risky through VirusTotal, assuming you have good upstream bandwidth.
www.virustotal.com
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Here are some suggestions for managing privacy and security on your computer:
Level 1 (foundation)
- Anti-virus (I use Sophos)
- Anti-malware (I use Malwarebytes)
- Firefox browser with ad blocking and Javascript blocking add-ons (I use AdBlock Plus and NoScript) for general web browsing. I keep Safari relatively stock and only use it with a very small number of trusted websites.
Level 2 (good to have if you don't mind the convenience vs. security tradeoffs)
- Little Snitch (monitor outgoing Internet connections, essentially a reverse firewall)
- RansomWhere (anti-ransomware monitor)
- SilentKnight (utility for easily checking Apple's own security measures in macOS for updates)
Another action you can take is to set up a non-Admin user account for daily use. Then you only need to log-in as an Administrator when you are actively doing troubleshooting, installations, or maintenance tasks (see:
https://forums.macrumors.com/thread...n-administrator-account.2327558/post-30700893).
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Have a look at
https://forums.macrumors.com/threads/security-protection-on-mac-how.2308465/post-30660294 and
https://forums.macrumors.com/thread...curity-suite-for-macosx.2310577/post-30375113 for more info on X-Protect and MRT, Apple's built-n macOS security software.
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Finally, my Mac security strategy is centered around risk management, not predictions of bad actors' behavior. I prefer spending some time up front–and money if justified–to minimize the possibility of having to deal with the fallout of an attacker putting viruses or malware on my computer. I view anti-virus and anti-malware software as a form of insurance. Yes, it sucks that I need it but I feel that having it lets me sleep better than not having it.
Also, we are all human and we make mistakes, especially when we are in a rush, distracted, or tired. Relying on constant vigilance as sole protection requires perfection. I don't think any of us can reach that standard very often, especially with something that is constantly changing and morphing.