Microsoft already offers antivirus protection with its operating systems in 1993, Microsoft Anti-Virus for MS-DOS. The current Microsoft Defender Antivirus started in 2005 as Microsoft AntiSpyware.
It was a bumpy ride, with the antivirus tool going by different names and sometimes earning it scores below zero in third-party testsbut with the release of Windows 10, Microsoft Defender antivirus became a respectable (if not glorious) malware-fighting tool. A consistent factor through all these changes: Microsoft’s protection has always been free.
Does that change? Many readers were alarmed by the recent announcement of Microsoft Defender for individualswhich – as Microsoft’s descriptive page makes clear – is only available as part of a paid subscription to the Microsoft 365 cloud-based office service. What happened to free?
Defender of last resort
When every PC on the Internet has antivirus protection, life gets harder for malware writers. It is more difficult for viruses to spread and less lucrative to install data-stealing Trojans when most potential victims antivirus protection† Even ransomware mills can’t arm so much money from victims if protection is universal.
That’s why Microsoft designed Defender to boot on any PC that doesn’t have a third-party antivirus. Near-universal antivirus offers some sort of herd immunity†
Does it work? Well, Microsoft has the numbers to show that this is the case. Representatives pointed out that the malicious software removal tool you see with almost every Windows update does more than just upgrade Defender. Unless you opt out, it offers: detailed (but not personal) information to Microsoft, including your operating system, any malware detections, and what third-party antivirus software is installed. And studies based on this information show that even unprotected PCs benefit from having antivirus programs on most of their connections.
Defender strives to maintain that herd immunity, without interfering with user choice 3rd party antivirus† If you install Bitdefender, Norton, McAfee or any other recognized solution, Defender ceases operations and watches silently from the background. But if you remove or (more likely) let the protection expire, Defender springs back into action. It’s about keeping your system protected in some way.
Defender is persistent. To test third-party antivirus programs without any intervention from Defender, I resort to tweaking the registry, changing Windows Service permissions, and editing Group Policy. Otherwise, Defender would destroy some of my samples in the time between starting a new test and completing the installation of a new antivirus.
The Microsoft Defender for individuals(Opens in a new window) announcement begins with a big splash: “Microsoft Defender. Online security, simplified. Easy-to-use online protection for you, your family and your devices with the Microsoft Defender app, now available to download with your Microsoft 365 subscription.” It caused readers to contact me in a panic. They have always relied on Defender (despite my admonitions to use a better one) free antivirus product† Will they have to change?
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Other entries in the announcement don’t make things clearer. For example: “Get one centralized view to manage and monitor your security status across your entire… computers and telephones” (emphasis mine). The answers to the frequently asked questions on “Do I need a Microsoft 365 subscription to use Microsoft Defender?” is a resounding “Yes”, and the FAQ says “No” to “Is Microsoft Defender built into the Windows operating system?”
Windows users don’t have to worry
Ultimately, there is no actual change in Microsoft Defender Antivirus on Windows. The new Microsoft Defender for Individuals strictly protects non-Windows systems. It offers antivirus protection on macOS and Android (but not iOS) and web protection on Android and iOS (but not macOS). Web protection refers to what Windows users know as SmartScreen Filter, which I’ve used in the past to protect only Microsoft browsers.
A blog post by Vasu Jakkali(Opens in a new window), Microsoft’s Corporate VP for Security, Compliance, Identity, and Management, finally makes it clear that this new offering of antivirus protection strictly extends to platforms other than Windows. It does not change the status of Microsoft Defender Antivirus. I must point out that the best macOS antivirus and android security products almost certainly do better. Few are available for free, but this new cross-platform Defender isn’t free either.
So if you rely on Microsoft Defender Antivirus for security, nothing will change. You can pay to extend protection to other platforms and manage it (and your Windows protection) from one central location. Better yet, you can install a third-party cross-platform platform security suite to take care of all your devices. But if you don’t do anything, Defender will still take care of you, as always.
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