Vulnerability Scanner vs EDR: Beyond the Tool, a Program

The False Debate: Scanner or EDR?

Should you use a traditional vulnerability scanner or rely on vulnerability management capabilities integrated into an EDR? This question, posed in binary terms, is actually a trap.

The real question is not "which tool?" but "which program to implement?"

Scanners and EDRs have complementary strengths. The challenge is to build a coherent strategy that leverages each at its best, within a global vulnerability management program oriented toward a precise objective: identify and block compromise paths.

Vulnerability Scanner: A Zone-by-Zone Approach

Why Scan Zone by Zone?

The method I recommend consists of deploying vulnerability scanners network zone by network zone, with a clear objective: map possible compromise paths.

Deployment Methodology

Zone-by-zone deployment is not just a technical matter, it's a structured approach:

1. Logical segmentation: Identify network zones (DMZ, production, office, industrial, cloud...)
2. Prioritization: Start with exposed zones (Internet-facing, DMZ) and critical ones (production, sensitive data)
3. Progressive scanning: Deploy zone after zone to avoid the "big bang" effect and refine the method
4. Pivot analysis: For each zone, identify assets that allow bouncing to other zones
5. Path mapping: Reconstruct possible attack paths from outside to critical assets

This approach allows answering a strategic question: "How could an attacker reach my critical assets?"

EDR: The Enriched Endpoint Vision

EDR Strengths in Vulnerability Management

Modern EDRs increasingly integrate vulnerability management capabilities. Their assets:

• Real-time visibility: permanent inventory of endpoints and their software
• No network impact: no active scanning, therefore no disruption
• Behavioral correlation: crossing vulnerabilities with suspicious behaviors
• Rapid deployment: agent already present, no new infrastructure
• Dynamic prioritization: focus on vulnerabilities exploited in the wild

Limitations of EDR Alone

But EDR also has blind spots:

• Limited coverage: only assets with agents (no legacy servers, IoT, network equipment)
• No network vision: doesn't see flows, possible pivots, segmentation
• Vendor dependency: variable quality of vulnerability detection depending on vendors
• No active scanning: only detects what's installed, not exposed services

ASM/EASM: The Missing Layer

Attack Surface Management (ASM) and External ASM (EASM)

ASM and EASM are essential building blocks to complement EDR and internal scanners. Their role: discover what you don't know you have.

Integration with EDR

Some EDRs now integrate ASM/EASM modules. This is excellent because it allows:

• Centralizing the vulnerability view (external and internal)
• Correlating a vulnerable external asset with connected internal endpoints
• Prioritizing according to the complete compromise path (external → internal)
• Detecting shadow IT and linking it to known endpoints

But beware: ASM/EASM is only effective if you know what to do with it. Discovering 1000 external assets without a remediation plan is just adding anxiety.

Beyond Tools: Building a Program

Not a Solution, a Global Program

Here's the truth vendors don't like: no tool solves the vulnerability management problem alone.

You must build a vulnerability management program that integrates:

Practical Approach: Where to Start?

Phase 1: Laying Foundations (months 1-3)

1. Inventory of existing: What tools do you already have? EDR? Scanner? ASM?
2. Network mapping: Identify zones, flows, critical assets
3. Define priorities: Which zones to scan first? Which assets to absolutely protect?
4. Structure the team: Who does what? Who prioritizes? Who remediates?

Phase 2: Progressive Deployment (months 4-9)

1. Deploy EDR: If not already done, this is the absolute priority (detection + vulnerabilities)
2. Scan first zone: Start with DMZ or most exposed zone
3. Activate ASM/EASM: Discover external attack surface
4. Correlate sources: Cross EDR, scanner, ASM for unified view
5. Prioritize quick wins: Critical vulnerabilities easily remediable

Phase 3: Path Analysis (months 10-12)

1. Map compromise paths: From external to critical assets
2. Identify pivots: Assets allowing bouncing between zones
3. Prioritize according to paths: Vulnerability on a pivot = high priority
4. Implement workarounds: Segmentation, micro-segmentation, WAF...

Phase 4: Industrialization (year 2)

1. Scan all zones: Complete IT coverage
2. Automate prioritization: Use AI to correlate and prioritize at scale
3. Integrate with SOC: Now that you have visibility, SOC can contextualize its alerts
4. Measure and optimize: Metrics, executive dashboards, continuous improvement

AI: Prioritization Accelerator

How AI Helps Concretely

With thousands of detected vulnerabilities, manual prioritization is impossible. AI enables:

• Massive correlation: Cross inventory, threat intelligence, known exploits, network position
• Exploitability prediction: Not just CVSS, but real probability of exploitation
• Critical path identification: Vulnerabilities that, combined, open a compromise path
• Workaround suggestions: When patching is not possible, AI can suggest compensations
• Ticket automation: Automatic generation of remediation requests with context

AI is an efficiency multiplier, not a miracle solution. It amplifies a good program but doesn't save a bad one.

Conclusion: The Program Approach Above All

Vulnerability scanner or EDR? The answer is: both, orchestrated in a coherent program.

This is not a 3-month project. It's a permanent program, because your IT evolves, attackers evolve, vulnerabilities appear every day.

But it's the only way to move from reactive and anxiety-inducing vulnerability management to proactive and controlled risk management.

The tool is only a means. The program is the end.