Harnessing Microsoft Defender and Sentinel: The Complete MDR Platform
Microsoft Defender XDR and Sentinel together form one of the most capable security operations platforms available. Here is how to get the most out of them — and why you need human operators, not just automation.
By Tom Brennan
Microsoft Defender XDR combined with Microsoft Sentinel represents one of the most capable and cost-effective security operations platforms available — particularly for organizations already in the Microsoft ecosystem.
The Platform Architecture
Microsoft Defender XDR
Defender XDR unifies signal across multiple protection layers: Defender for Endpoint (EDR), Defender for Office 365 (email), Defender for Identity (Active Directory), Defender for Cloud Apps (CASB), and Defender for Cloud (cloud workload protection).
Microsoft Sentinel
Sentinel aggregates signals from Defender, Azure, and hundreds of third-party connectors. It enables custom detection rules, automated playbooks (SOAR), and long-term data retention for threat hunting.
Why Automation Alone Is Not Enough
Sophisticated adversaries specifically design their techniques to evade automated detection. Human-led threat hunting catches what automated rules miss. This is the core of what Proactive Risk's 24/7 MDR service delivers on top of the Microsoft platform.
Common Configuration Gaps
- Defender for Identity not connected to domain controllers
- Sentinel retention configured too short for effective threat hunting
- Alert fatigue from poorly tuned detection rules
- Incident response playbooks not tested
Free MDR & Incident Response Resources
Strengthen your detection and response capabilities with Proactive Risk's free resources, available in the Downloads library:
- Security Incident Response Plan (SIRP) Template — a ready-to-use incident response plan template aligned to NIST SP 800-61, covering detection, containment, eradication, and recovery
- Proactive Risk GitHub Repositories — open-source security automation scripts and detection tools published by the Proactive Risk team