If your Mac is behaving strangely, like for example if you see weird ads where they normally wouldn't, or it's become very slow, your computer might be infected with a virus from an app downloaded from an untrusted source, or For other reasons.
If you are worried that your computer has been infected with a virus, you can run a virus scan on your operating system. Here's how:
Can Mac computers catch viruses?
Despite the common belief that Mac computers are immune to viruses, they can still be infected with viruses. Here are examples of some of the most common viruses found on Mac computers:
Silver Sparrow virus: Targets Mac computers running the M1 chip. It uses the JavaScript API installed in macOS to execute commands and is known to connect to its servers every hour.
GoSearch22 virus: Also known as Pirri, this is the first malware to target Mac computers with the M1 chip. Viruses themselves are adware and add ads in places where they would not normally appear.
ThiefQuest Virus: This is a virus that steals data from files on your computer.
LoudMiner: A crypto-mining virus that spreads via fake copies of the Ableton Live app.
How do you know if your Mac has a virus?
Mac computers can become infected with viruses by downloading applications and software from untrustworthy sources. So if you don't have any apps installed outside of the Mac App Store, don't worry. Your computer is less likely to get a virus if macOS and your browsers are up to date.
If you install an app outside of the Mac App Store but definitely need to search the web for the app and make sure it's completely safe before you install it, don't worry.
On the other hand, if you use a virus-infected USB flash drive or download an attachment from an email without backing it up, the virus can spread to your computer in several ways. There are several signs that your Mac computer may have a virus, including the following:
1- Ads and pop-ups appearing in unexpected places:
If you see an ad that you haven't seen before, it may be because you installed an app or downloaded a dangerous file outside the App Store. Your computer may be infected with a virus.
2- Your Mac computer suddenly slows down:
Some malware can make your computer part of a botnet, which is a network of infected computers controlled remotely by cybercriminals. (distributed denial of service) on certain websites, or running CPU-intensive tasks that constantly slow down your computer.
To be absolutely sure that your computer does not have any viruses, use a free antivirus program such as:
- Bitdefender: This app identifies viruses for manual removal, it does not remove viruses, it only detects their location.
- Malwarebytes for Mac: This app scans the entire Mac operating system and removes malware in less than 30 seconds.
- ClamXAV: This is the Mac version of ClamAV, an open source antivirus that detects viruses and malware on your computer.
If none of these tools detect viruses, it is very unlikely that your computer is infected with a virus.
Antivirus features built into Mac computers
In addition to the ability to download antivirus software, Mac computers have built-in tools to protect against malware and viruses, including:
Gatekeeper
Gatekeeper prevents users from installing potentially malicious software. By default, the program blocks installation of apps outside the Mac App Store, but you can change the settings to block downloads of apps from unknown developers.
Many Mac users disable Gatekeeper completely, which allows them to download any software from various potentially unsafe sources, leaving the computer vulnerable.
Sandbox application
App Sandbox is a feature of the macOS operating system whose main function is to protect system resources and user data from malicious apps by preventing them from accessing file system, network connections, etc.
X Protect
X Protect is anti-malware software that's been included with macOS since 2009, but unlike Windows Antivirus, the program is invisible to most users.
You cannot open the program and run a scan yourself or install updates manually. However, the program can warn you if your Mac is infected with a known virus. It also prevents you from opening infected files.