“Is Microsoft Defender enough?” is the single highest-intent security question SMBs are asking in 2026 — and it deserves an honest answer, not a fear pitch. Defender for Business is a legitimately strong product at a great price. The honest answer is: it’s a strong foundation, and it’s incomplete. Here’s the line between the two.

Where Defender for Business is genuinely good

Credit where it’s due. Defender for Business gives you:

  • Solid Windows endpoint protection with next-gen antivirus and behavioral detection.
  • Attack-surface-reduction rules and basic EDR capabilities.
  • It’s bundled into Microsoft 365 Business Premium, so the price is hard to beat.

If you’re a Windows-only shop looking for baseline endpoint defense, Defender covers a lot of ground for the money. Keep it.

Where the gaps are

The problem isn’t that Defender is bad — it’s that the modern SMB attack doesn’t stay on the Windows endpoint. The data shows where attackers actually go:

  • BEC and funds-transfer fraud are 58% of all cyber-insurance claims (Coalition 2026) — and default M365 filtering routinely lets BEC through, because there’s no malware to scan.
  • 97% of identity attacks are simple password attacks (Microsoft Digital Defense Report 2025) — and catching impossible travel, MFA fatigue, and OAuth abuse requires ITDR that Defender for Business doesn’t include (you’d need Entra ID P2 at ~$9/user/month).
  • Identity is now the primary intrusion surface, not endpoints (Coveware Q4 2025) — which is precisely where Defender’s endpoint focus is weakest.
  • Defender’s Mac and Linux coverage lags its Windows coverage, and cyber-insurance carriers ask for EDR across all three.
  • After-hours response is on you. Defender raises alerts; it doesn’t staff a SOC to act on them at 3 a.m.
  • Defender can’t generate the cyber-insurance readiness report your underwriter now wants.

Put simply: Defender watches one surface well. The attacks that cost SMBs the most live on the others.

Supplement, don’t replace

The smart move isn’t to rip Defender out — it’s to keep it as your Windows endpoint baseline and add the surfaces it doesn’t cover. This is the same supplement-not-replace pattern the market has converged on, and it avoids the cost and disruption of a forklift migration.

How Centeye complements Defender

Centeye sits alongside Defender and closes the gaps it leaves:

  • Email & BEC — dual-cloud detection that catches the phishing and BEC default M365 filters miss.
  • Identity / ITDR — impossible travel, MFA fatigue, token theft, and OAuth risk across Entra, Google Workspace, and JumpCloud, without paying for Entra P2.
  • Endpoint / EDR — behavioral detection across macOS, Windows, and Linux, with the ransomware trifecta and 51 Sigma rules.
  • Dark Web, WAF, DNS/C2, and Shield-AI — the surfaces no endpoint tool watches.
  • Kavach provides the after-hours response Defender leaves to you, and Argus writes the cyber-insurance report Defender can’t.

Keep Defender. Add the rest. That’s the honest recommendation.

Wondering about the difference between EDR and MDR? Read EDR vs. MDR for small business. Want to see what Centeye adds on top of Defender? Get a demo.

Figures cited from the Coalition 2026 Cyber Claims Report, the Microsoft Digital Defense Report 2025, and the Coveware Q4 2025 Ransomware Report. Centeye is a supplement to, not a replacement for, Microsoft Defender.