I would like to share my experience with you and talk about viruses created for Mac devices and how to deal with them. You may say that there are no Mac viruses as Apple does not allow it. However, I may say that there are plenty of nasty malware
types like adware that open new tabs in your browser, redirect you to irrelevant pages and show numerous popups.
Yes, these are not real viruses. Adware like Search Marquis cannot clone itself and infect other connected devices. It cannot encrypt your files or cause any other harm. Its activity is related only to web redirects and excessive advertising. At the same time, who knows which rogue websites adware may land you on next time. It may happen that you end up on a phishing website where cyber crooks harvest personal information that leads to identity theft.
I strongly recommend removing all adware that penetrated your device. But there is a problem here. If you want to get rid of Mac adware, you cannot quickly find a solution. If you go to google and search there how to get rid of Mac malware, you will see that all top results offer you to buy and install some shady software. In reality, these Mac antiviruses do nothing, as we know that the Apple ecosystem does not allow apps to access other apps' data. No antivirus can really scan and check your files.
How to remove Mac malware
If your system is infected with adware and you do not know how to get rid of it, you may try to call Apple and ask what to do. You can find their phone number here: support.apple.com/en-gb/HT201232#us-ca.
Another option is to try your luck on Apple communities. Thousands of tech enthusiasts help uses with their problems there. Here is a sample thread: discussions.apple.com/thread/8226644.
There are other options too. Apple operating systems are not very difficult to use, and any person can remove adware manually by going through step-by-step guides posted on numerous malware removal websites. Here is a guide by BitAdvisors.com on how to remove Search Marquis malware.
Most rogue software works by exploiting bugs and vulnerabilities in your computer's operating system. And macOS has its own bugs too. To fix these vulnerabilities, Apple periodically releases operating system updates. To date, macOS has not proved attractive enough for cybercriminals and evil developers to flood it with malware.
To stays away from any surprises, it is recommended to update your OS as well as all apps installed regularly.
You should never install apps from unofficial app stores not controlled by Apple.
One of the ways for adware to penetrate your Mac computer is through bundled installs. You download and install a very useful app that is often free, but in reality, you get several apps. People never read user agreements written in small print. There it can be noted that you agree to install additional tools and provide some rights to them. Whenever you install something, be careful and read user agreements, and do not miss additional unnecessary software.
Do not install any software without urgent necessity. Any additional software widens the attack surface.
To be able to do bad things, current Mac malware requires users to perform some actions – grant rights. So, be careful with allowing any app to access your data, change settings, etc.
One more wise move is to make backups. iCloud or ordinary flash drives will help you not lose your data in case of a system glitch or malware attack.
Final advice - do use VPNs. Your connection will be encrypted, and attackers will not be able to find where you are actually located or what data your traffic consists of.