🔥 The Hidden Risk of “Wide Open” Internal Policies — And How To Remove Them Safely

In one of my recent projects, I noticed a wide open internal traffic policy in place.
Later, I was asked to work on this issue and remove the wide open policy — but with one strict condition:

👉 No production impact.

The environment had:
👉 Allow Any → Any → Any for internal zones

Yes — it keeps production safe from outages.
But from a security architecture perspective — it’s a ticking time bomb.

Wide open internal policies:
❌ Break segmentation strategy
❌ Increase lateral movement risk
❌ Violate Zero Trust principles
❌ Hide real application dependencies

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The Real Challenge

The question is not “Should we remove wide open policy?”
The real question is:

👉 How do we replace it with granular policies without breaking production?

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🛠 Step 1 — Observe Before You Enforce

Start with visibility, not restriction.

✔ Enable logging on the wide open rule
✔ Pull traffic logs (7–30 days minimum)
✔ Identify:
• Source → Destination pairs
• Applications actually used
• Ports actually used
• Business critical flows

This becomes your real traffic baseline (not assumed traffic).

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🧱 Step 2 — Build Granular Policies in Parallel

Create new rules ABOVE the wide open policy:

➡ App-based rules
➡ Service-specific rules
➡ Source/Destination zone segmentation
➡ User-ID if applicable

Important:
Do NOT remove wide open yet.
Let new rules “shadow learn” real traffic.

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📊 Step 3 — Validate Using Hit Count + Logs

Before touching wide open rule:

Ask these questions:
✅ Are new rules getting hits?
✅ Any unexpected deny logs?
✅ Any spike in helpdesk tickets?
✅ Any app teams reporting slowness / drops?

If yes → Adjust policies.
If stable → Move forward.

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🚨 Step 4 — Controlled Reduction (Not Instant Removal)

Instead of deleting wide open:

Phase approach:
Week 1 → Restrict known unused apps
Week 2 → Restrict unused ports
Week 3 → Restrict unknown source segments
Final → Convert to temporary fallback rule

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🧪 Step 5 — Safe Removal Strategy

Before final removal:

✔ Confirm zero hit count for X days
✔ Take policy snapshot / config backup
✔ Inform app owners + infra teams
✔ Remove during low business window

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🏗 Architect Mindset vs Engineer Mindset

Engineer mindset → “Traffic works, leave it.”
Architect mindset → “Traffic works, but is it secure, observable, and controlled?”

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💡 Pro Tip:
If you are afraid to remove a wide open rule, it usually means you don’t have visibility yet — not that you need the rule.

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Have you ever inherited an environment with wide open internal policies?
How did you approach cleanup without causing outages?