Why I Encouraged a Peer IT Leader to Switch to Microsoft Defender

Paul Riley – April 12, 2025  – 6 mins read

A few months ago, a peer of mine — IT Director at a mid-sized law firm — gave me a call. He was knee-deep in vendor evaluations for endpoint protection, threat management, and compliance tooling. “We’re juggling three security systems,” he said. “It’s messy. Overlapping features, conflicting alerts, and the partners want answers when anything looks remotely like a breach.”

Sound familiar?

He asked what we were using — and I told him, without hesitation:
“We moved everything to Microsoft Defender. And honestly, I wish I’d done it sooner.”

Here’s What I Told Him:

1. You’re Already Paying for It

Like many firms, his was already deep into Microsoft 365 — Exchange Online, SharePoint, Teams. Yet they were paying for third-party AV, threat detection, and DLP tools that didn’t integrate cleanly with their core stack.

Defender comes bundled with Microsoft 365 E5 (or as a cost-effective add-on to E3). I said:
“Before you renew that AV license again, look at what Defender gives you — real endpoint protection, attack surface reduction, automated investigation, and tight integration with Microsoft compliance tools.”

For a mid-sized firm, cost efficiency without sacrificing capability is a win.

2. The Integration Is a Game Changer

One of his pain points? Incident response was a nightmare. They had security data in one place, compliance logging in another, and user identities somewhere else. Nothing talked to each other.

Defender unifies:

• Endpoint protection (Defender for Endpoint)
• Email and collaboration security (Defender for Office 365)
• Identity protection (via Azure AD & conditional access)
• Compliance tools (via Microsoft Purview)

I told him:
“When we made the switch, suddenly our SOC had a full picture. When something suspicious happened, we knew exactly where it started, who touched it, and what it could impact — without pulling logs from five systems.”

3. The Real-Time Threat Intelligence Is Actually Useful

He was concerned about being flooded with alerts. I said, “You’ll still get alerts — but they’re smarter.”

Microsoft’s global threat intelligence gives Defender a real edge. We’ve seen it detect phishing campaigns in real-time and isolate compromised endpoints without user involvement.

One of our most telling moments? A staff member clicked a dodgy OneDrive link. Defender caught it, quarantined the process, and logged the entire event chain — before the user even logged a ticket.

4. Compliance Was the Sleeper Benefit

What really surprised me, and what I stressed to him, is how much Defender helped us with regulatory alignment.

As a global firm, we deal with GDPR, client confidentiality standards, ISO27001, and internal policy audits. Defender, paired with Microsoft Purview, gave us:

• Auditable trails
• Retention and DLP controls
• Communication compliance for Teams and email
• Easy export for board-level risk reviews

“You’ll save time and stress on audits,” I told him. “You won’t be scrambling to explain how data is protected — you’ll have dashboards showing it in real time.”

5. Just Watch for Legacy Identity Gaps

No system is perfect. I gave him one caution: Defender assumes a modern identity infrastructure. If you’re still running legacy on-prem apps without SSO or modern authentication, it can be tricky. We hit this ourselves — had to implement hybrid identity strategies and conditional access policies that weren’t out-of-the-box.

But that’s not a dealbreaker. It just needs planning.

The Result?

Two months after that conversation, he rolled out Defender for Endpoint and Defender for Office 365 firm-wide. He dropped two old systems and has already seen fewer helpdesk tickets for AV errors, better visibility into phishing attempts, and happier compliance officers.

“It’s not just cheaper,” he told me recently. “It’s smoother. I don’t feel like I’m stitching together a security stack anymore.”

Final Thought: Defender Is Ready — and Worth It

For years, we treated Microsoft’s security stack like a backup singer. Now it’s the lead.

If you’re already in the Microsoft ecosystem, Defender isn’t just “good enough” — it’s often better than the more expensive alternatives that don’t integrate. And as legal IT leaders, reducing friction, improving visibility, and strengthening compliance is exactly the kind of quiet win we need.