Antivirus is software that stops known malware on a single device. MDR (Managed Detection and Response) is a service in which analysts continuously monitor your entire environment, spot unusual behavior and step in immediately. Antivirus remains the foundation. MDR catches what slips through, such as an attacker who logs in with a stolen password and doesn't need a single file.
Antivirus is strong at quickly detecting known malware. When it finds some, it quarantines it straight away. Below you can read what antivirus does well.
An employee opens an attachment named "invoice_0923.zip". Inside is a known ransomware variant. Defender recognizes the fingerprint, quarantines the file and the employee barely notices. At most, a notification in the bottom right of the screen.
Put very simply, this is how antivirus works. It compares files against a database of known malware and applies rules to suspicious behavior by programs on that one device. Modern scanners also draw their knowledge from the cloud, so a variant that surfaced in Australia this morning can be stopped on your laptop this afternoon.
And it demonstrably works. In the Business Security Test by AV-Comparatives (March through June 2026), Microsoft Defender stopped 395 of 400 real-world attacks, without a single false alarm. AV-TEST awarded Defender the Top Product label in April 2026.
Infected downloads, old ransomware or malware that is still circulating: a well-configured virus scanner stops most of what cybercriminals throw at you. For your devices, that's already quite a lot. It's just no longer enough.
Of all the detections CrowdStrike made in 2024, 79% were malware-free. In 2019 that was still 40%. Attackers log in with stolen passwords and use the programs that are already on your systems (source: CrowdStrike Global Threat Report 2025).
To traditional security, meaning antivirus plus a firewall, such an attack looks like a colleague who is simply doing their job. No alarm goes off, because there is nothing the scanner has been trained to look for.
Antivirus recognizes what it already knows. That sounds logical, but that is exactly where the gap is.
Between the moment a new malware variant appears and the moment it lands in the database, time passes. Sometimes a few hours, sometimes days. And targeted attacks on a single company often never get a signature, because the malware was built specifically for that one company. That doesn't mean antivirus can't detect it later, but you want to stop threats before they damage your systems.
The behavioral rules in modern scanners catch some of this. But they only look at one device at a time and have to decide in a fraction of a second between blocking and allowing.
What we often see in practice, and what the CrowdStrike report also shows, is that many cyberattacks start with stolen credentials that trigger no alert, because the activity looks like normal behavior. On top of that, antivirus can't step in against malicious login attempts at all, because it only looks at the device it runs on.
Antivirus looks for malicious files. But when a hacker uses the software and files that are already on the device, antivirus sees it as normal behavior. Take an attack we often come across at small and medium-sized businesses.
Monday morning, 08:12. Someone logs in to the Microsoft 365 account of your finance employee. The password came from a data breach at a webshop and the MFA prompt was approved half asleep. At that moment the attacker has taken over the account and creates a mailbox rule that moves every email with "invoice" in the subject line to the archive folder. Then two customers receive an email with a new IBAN.
Which file should the virus scanner have stopped? None. There's a login, a rule and an email. Three areas where antivirus has no visibility.
The same applies to attackers who use built-in Windows tools inside the network, such as PowerShell and Remote Desktop, or who quietly create an extra admin account. Those are legitimate programs and ordinary actions, so the scanner lets them through. Antivirus looks at the device it runs on. It doesn't track how processes together form an attack.
Your antivirus is on day and night. Nobody is watching, though.
An alert appears on a laptop that's closed in a bag, or in a management console that won't be opened again until Monday. And attackers choose that timing deliberately: Friday evening, a public holiday, the first week of the summer holidays.
CrowdStrike measures breakout time, the time between initial access and the moment an attacker moves further into the network. On average 48 minutes. The fastest: 51 seconds. If an attack starts at nine on Friday evening and you read the alert at nine on Monday morning, you're looking at something that has been going on for 60 hours. If you got an alert at all.
Among other things, MDR does threat detection. The system learns what your environment looks like on a normal day and flags anything that deviates:
Looked at one by one, it's hard to tell whether these signals are a threat. A colleague on holiday in Lisbon also logs in from abroad. That's why MDR puts signals side by side. A login from abroad, followed within five minutes by a new mailbox rule and an MFA approval from an unknown device: that's a very different story from someone quickly checking their email on the beach.
An alert is only worth something if someone acts on it. With antivirus, the tool acts on its own, provided it recognizes the threat. With MDR, a team of specialists does this. As soon as a cyberattack is confirmed, the team can:
With Peakproteqt's MDR Premium, we aim to step in within 15 minutes of detection, including outside office hours and on weekends.
The answer: supplement it. With antivirus vs MDR, you don't have to choose. Antivirus and endpoint protection form the first layer. MDR is the layer behind it, for everything that first layer doesn't see.
There is one situation in which you do replace something. Some MDR services supply their own agent that also handles prevention. A separate paid scanner alongside it then makes little sense, and two scanners on one laptop often get in each other's way. That can lead to double scans, slow machines and programs blocking each other.
If you use Microsoft's antivirus, you usually already have a solid foundation. We build on top of it. Our tooling works alongside that antivirus, so you don't have to remove it everywhere.
Adding MDR makes sense if:
Most customers who take MDR with us see within a week what isn't configured properly and what's going on inside their company. Without that monitoring, they would never have known. That's why MDR is more than just stopping cyberattacks. It also gives you insight into your business.
