Defender for Business vs CrowdStrike vs SentinelOne for SMBs

For a small business on Microsoft 365 Business Premium, Defender for Business is the endpoint protection to start with, because you already own it and it covers the essentials: next-generation antivirus, endpoint detection and response, attack surface reduction and automated investigation, all managed from the Microsoft Defender portal. CrowdStrike Falcon and SentinelOne Singularity are the better choice when you need coverage the Microsoft product lacks for your environment, such as Linux servers, when you want a single platform across a company that is not standardized on Microsoft, or when you are buying a managed detection and response service built on one of them. All three are credible EDR platforms that meet what cyber insurers now ask for. The decision is about fit and about who watches the alerts, and this comparison covers both.

What do Defender for Business, CrowdStrike and SentinelOne have in common?

All three replace traditional antivirus with an agent that watches behavior rather than matching known files. All three record what happens on the machine (processes, network connections, file changes, credential use), send that telemetry to a cloud console, flag suspicious chains of activity, and let an analyst isolate a computer from the network with one click. That is what endpoint detection and response means, and our earlier article on EDR, antivirus and MDR explains why it matters for ransomware.

All three also carry the same caveat. An EDR agent generates alerts; it does not resolve them. Somebody has to read the alert at 11 p.m. on a Saturday, decide whether it is real, and act. The product you choose is half the decision. The other half is who is on the other end of the console.

What does Defender for Business include if we already have Business Premium?

Microsoft designed Defender for Business for companies with up to 300 employees and bundled it into Microsoft 365 Business Premium, with a standalone version for businesses on other plans, as described in Microsoft's Defender for Business overview. It includes next-generation antivirus, endpoint detection and response, attack surface reduction rules that block the common ransomware tricks (Office macros launching scripts, credential theft from memory), automated investigation and remediation, and vulnerability management that shows which devices are missing patches or running risky software. Servers are covered through a separate servers add-on.

The practical advantage is integration. Defender for Business shares the Microsoft Defender portal with Defender for Office 365, which Business Premium also includes, so a phishing email and the malware it dropped appear in the same incident. Device compliance flows to Intune and Conditional Access, so a machine with an active alert can be blocked from opening company email until it is cleaned. For a business that already lives in Microsoft 365, that is a lot of security with nothing new to buy. Our Microsoft 365 security service is built around turning all of it on properly, which is the step most small businesses skip.

The limits are real too. Linux is outside its scope at this tier. Some advanced hunting and automation features are reserved for the enterprise Defender for Endpoint Plan 2. And the portal, while capable, assumes someone will log in and look.

What do CrowdStrike and SentinelOne add?

CrowdStrike Falcon is a cloud-managed platform built around a single lightweight agent, sold in bundles that start with small-business tiers and scale up to packages with threat hunting and identity protection, as listed on CrowdStrike's pricing page at the time of writing. It covers Windows, macOS and Linux from one console, and its managed service, Falcon Complete, is one of the reasons many MDR providers build on it. CrowdStrike's threat intelligence and its visibility across a large customer base are its selling points.

SentinelOne Singularity takes a similar approach with a different emphasis. Its agent reconstructs each attack as a storyline, so an analyst sees the whole chain from the first email attachment to the last encrypted file rather than a pile of separate alerts. On Windows, its rollback feature can return files changed by ransomware to their pre-attack state using the system's snapshot capability, which has saved more than one small business a very bad week. It also covers Linux, and its managed response service, Vigilance, is sold separately, as described on SentinelOne's platform page.

Both vendors publish tiers, and the differences between tiers matter more than the differences between vendors. The entry tiers on either side are strong EDR. The higher tiers add identity protection, network visibility, hunting and longer data retention, which is where a growing company with a security lead gets value and a ten-person office does not.

Who watches the alerts?

This is the question that should drive the purchase. A business with no security staff has three options. It can rely on the automation built into the product, which handles clear-cut malware well and ambiguous activity poorly. It can buy the vendor's managed service, which puts the vendor's analysts on your alerts around the clock. Or it can contract a managed detection and response provider that runs one of these platforms for many clients and responds on your behalf.

The third option is how most small businesses end up protected, and it changes the vendor comparison. When an MDR provider does the watching, you inherit their platform choice and their playbooks, and what you should evaluate is the provider: response times in writing, what they are authorized to do without calling you, and whether they will also handle the Microsoft 365 side of an incident. We run managed detection and response that way, with the same engineers who manage the client's environment doing the responding, and our track record over three years is more than 30 ransomware incidents handled with every one fully recovered.

One lesson from the CrowdStrike outage in July 2024 applies to every vendor here: any agent with deep access to the operating system can take a machine down if an update goes wrong. Ask how updates are staged and whether you can hold a ring of devices back. We wrote up the continuity lessons from that day at the time.

Which one do cyber insurers accept?

All three. Insurance applications in 2026 ask whether you run endpoint detection and response on every workstation and server, whether it is monitored around the clock, and whether multi-factor authentication covers email and remote access. They rarely name vendors. Defender for Business, Falcon and Singularity each satisfy the EDR line, and the monitoring line is answered by whoever watches the console. Our guide to cyber insurance requirements lists the controls underwriters ask about, and the answer you give should match what is on the machines, because a claim can turn on it.

Which endpoint platform should a small business choose?

Choose Defender for Business if you are on Microsoft 365 Business Premium and your fleet is Windows and Mac. You already own it, it integrates with the identity and email protection you also own, and the money you save belongs in monitoring, backups and training rather than a second EDR license. Choose CrowdStrike or SentinelOne if you have Linux servers, a fleet that is not standardized on Microsoft, a security lead who will use the hunting and retention features, or an MDR provider whose service is built on one of them. If you are choosing an MDR provider first, let their platform decision stand and judge them on the service.

Do not run two of these on the same computer. One EDR agent per device, configured fully, with the portal watched by someone accountable, beats two half-configured agents fighting over the same processes.

Frequently asked questions

Is Defender for Business good enough for a small business?

Yes, for a company on Microsoft 365 Business Premium with Windows and Mac devices, provided it is fully configured and someone monitors it. It includes antivirus, endpoint detection and response, attack surface reduction and automated investigation, and it ties into Intune and Conditional Access. Its gaps are Linux coverage and the advanced hunting features reserved for the enterprise plan, which most small businesses do not use.

Is CrowdStrike or SentinelOne better for a small business?

Both are strong, and the difference between their tiers matters more than the difference between the vendors. CrowdStrike is known for its threat intelligence and its managed service; SentinelOne is known for attack storylines and Windows rollback. For a small business, the practical answer is usually whichever one your managed detection and response provider runs, because the provider's response is what you are paying for.

Do we still need MDR if we buy CrowdStrike or SentinelOne?

You need someone to watch the console, whatever platform you buy. That can be the vendor's own managed service, a managed detection and response provider, or a security employee on call. Buying a top-tier EDR product and leaving the alerts unread is the most common mistake we see in small-business incident response, and it is the setup ransomware groups count on.

Can we run Defender for Business alongside another EDR product?

Not as two active protections on the same device. When a third-party antivirus is registered as primary on Windows, Defender's antivirus steps into passive mode, and running two EDR agents together causes performance problems and gaps in coverage. Pick one platform per device, configure it completely, and remove the old agent as part of the rollout.

If you want a straight answer on which platform fits your fleet and who should be watching it, our managed detection and response service covers the endpoint platform, around-the-clock monitoring and response on a month-to-month agreement, and a free Tier 1 external penetration test will show you what an attacker sees from outside before you decide anything.