With so many free security products on the market, it is hard to know what is worthwhile. Here's a Malware Analyst's perspective on the best.
RING Ø LABS
This article is not sponsored by any of the products mentioned. These are my observations as a malware analyst regarding various antivirus products' detection rates over the years. The video at the end provides demonstrations of the products and additional explanations of their protections.
Honorable Mentions: AVG, AVAST, AD-AWARE
You've no doubt heard of these three products at some point. They offer decent signature protection and can easily be found by searching for free antivirus.
Due to the prevalence of these free products on systems, many malware authors develop avoidance techniques for the signature detection these solutions employ.
These 3 antivirus products have also started to enact sketchy business practices by bundling added programs or advertisements with their software. This isn't a good sign when dealing with security products.These also display an unusually high amount of messages/popups to include warnings, detections, updates, etc that the common user would likely be confused by.
All three products are certainly not bad to have, but there are better products out there.
Ole' Faithful: Windows Defender with EMET
Modern versions of Microsoft Windows include Windows Defender. It can be found easily by going to your start menu and typing defender. If you don't have another antivirus running there is no reason this product shouldn't be turned on. It provides decent protection against most malware I've seen throughout the years and can consistently be seen in virus-total hits.
You can further your protection with a free tool from Microsoft called Enhanced Mitigation Experience Toolkit. This turns on certain features in Windows that help mitigate against certain types of attacks that could bypass other security products.
Friends/Family IT Support Guru: Sophos
If you're a little tech savvy you've inevitably been asked by friends and family to help with a computer issue or which antivirus is the best/do you use? Due to its great detection rates, Man In The Middle (MITM) traffic inspection capability, and ease of use; I highly recommend Sophos for the family tech guru who installs AV on other people’s machines. The online dashboard feature allows you to remotely scan and view logs of remote machines. This can help troubleshoot problems and give you insight into potential issues. This product is also available on all three major operating systems: Windows, Mac, Linux.
2nd Runner-Up: Bitdefender
Over the years I have consistently seen BitDefender in the vast majority of virus detection results I've viewed. The features offered by their free product are quite limited, but this can be a good thing. The simpler the better for most people. Combine this simplicity, great detection, and outstanding system resource performance BitDefender is truly among the best free antivirus products on the market.
Gold Standard (With Caveats): Kaspersky Free
Outstanding. No other word comes to mind when I think of the protection offered by Kaspersky antivirus. Throughout my career, no other product has proven itself more in detecting emergent security threats and malware than Kaspersky. The paid product has traditionally followed a subscription based model, however, as of July 2017, Kaspersky has released a free edition of their antivirus software. It offers the same detection engine employed by their paid version and is quite light on system resources. There is also an included VPN (with data restrictions) that automatically offers to connect if it notices detects an unsecured/unknown wireless network. This is a great feature for those who travel a lot.
The caveat to this product is that Kaspersky labs have been shrouded in controversy over allegations of its dealings with the Russian Government (they are a Russian based company), spy agencies, and other clandestine activities. Is it true? Who knows. If you take all of the conspiracy theories out of the equation, you are left with an outstanding antivirus product that just got even better by offering a free edition to the world.
You can watch a full review and demonstration of each product here: