What is Microsoft Defender?
Microsoft Defender is not one product but a whole family of security products from Microsoft. At one end you find Windows Defender (officially Microsoft Defender Antivirus), the free antivirus built into every Windows PC. At the other end sit business solutions such as Defender for Business, Defender for Endpoint and Microsoft 365 Defender (today Microsoft Defender XDR), which protect the entire organisation as a whole: devices, email, identities and cloud apps. The full portfolio is documented on Microsoft Learn.
For a Danish business, the most important thing to understand is where the line runs between the free protection and the editions actually built to run security across many employees.
Windows Defender vs. Defender for Business: what is the difference?
Windows Defender protects the individual PC against known malware, and it actually does so quite well. But it is designed for private users: there is no central overview, no shared policies and no alert to IT when something goes wrong on a colleague's machine.
Defender for Business is built for companies with up to 300 employees and is included in Microsoft 365 Business Premium. Here you get central administration of all devices, automated vulnerability management, attack surface reduction and, most importantly, EDR: the ability to detect and respond to attacks in progress, not just block known viruses. It is the difference between a smoke alarm in one room and a full alarm system with a monitoring centre.
Is Defender enough as antivirus?
As pure antivirus: yes, the built-in Defender consistently performs well in independent tests. But for a business, antivirus alone is not enough. Modern attacks such as ransomware typically start with phishing or stolen credentials and move through the network before anything "classically" virus-like even happens. That requires central management, monitoring and a response plan, not just a product that scans files. The Danish Centre for Cyber Security recommends the same layered approach in its guidance at cfcs.dk. Honest answer: the Defender technology is very good, but without someone configuring, monitoring and responding, you only get a fraction of the value.
What is Defender for Endpoint?
Defender for Endpoint is Microsoft's full EDR solution (Endpoint Detection and Response) for larger environments, the big brother of Defender for Business. EDR means, in short, that the system continuously records what happens on each device (processes, network connections, changes) and uses that to detect attack patterns, isolate compromised machines and roll back damage. It comes in Plan 1 and Plan 2, where Plan 2 adds advanced hunting in the data and automated investigation, among other things. Its logs can also be forwarded to a SIEM such as Microsoft Sentinel for visibility across the entire environment.
How MI Support IT can help
As a certified Microsoft partner, we help you choose the right Defender edition, configure it correctly and keep an eye on the alerts afterwards. Read more about IT security and Microsoft 365, or contact us for a security review of your current setup.