Pomoc zdalna
Pomoc zdalna
2025-12-03

NGFW Without SSL Inspection – Why It Misses the Point

Modern network security must see what is actually happening

A decade ago, most Internet traffic was sent in plain text (HTTP). Firewalls based on IP addresses and ports were usually enough to control access and block basic threats.
Today, the situation is fundamentally different.

More than 95% of global web traffic is encrypted using HTTPS. Encryption protects users — but it also hides malicious activity from security systems that were not designed to inspect encrypted traffic.
This is where many NGFW deployments quietly fail.

A Next Generation Firewall without SSL/TLS Inspection cannot see the content of most network traffic. As a result, its most advanced security features are never truly used.

What makes a Next Generation Firewall different?

Compared to a traditional firewall, an NGFW can:

  • Detect and block application-layer attacks using technologies such as IPS (Intrusion Prevention System) and WAF (Web Application Firewall).
  • Analyze downloaded content using antivirus and malware detection engines.
  • Control access to websites and applications using Web Filtering and Application Control.
  • Build security policies based on user identity and group membership, not only IP addresses.
  • Provide QoS, DoS protection, multi-WAN handling and VPN services.

This makes NGFWs extremely powerful, but their effectiveness depends entirely on visibility.

Why NGFW security engines fail without SSL Inspection

Most traffic is encrypted

HTTPS is no longer an exception – it is the default. For users, this is transparent.
For a firewall, it creates a serious limitation.

Without SSL/TLS Inspection, an NGFW can only see:

  • source and destination IP addresses,
  • port numbers,
  • limited TLS metadata (such as SNI).

It cannot see URLs, payloads, downloaded files, form data or API calls.

Encrypted traffic hides real threats

Threat actors are well aware of this limitation. Today:

  • malware is delivered over HTTPS,
  • phishing pages use valid certificates,
  • command-and-control traffic is encrypted,
  • application-layer attacks are embedded inside TLS sessions.

According to industry research, over 87% of modern cyber threats are delivered through encrypted traffic.
Without decryption, the firewall simply does not see them.

Security features are technically enabled – but practically useless

IPS, AV, WAF and application control engines require access to traffic content.
If the traffic remains encrypted:

  • IPS rules cannot inspect exploits,
  • AV engines cannot analyze files,
  • web application attacks pass unnoticed,
  • application visibility is limited to domain names only.

In such scenarios, an NGFW behaves more like an expensive L3/L4 firewall than a true security platform.

How SSL/TLS Inspection actually works

To properly analyze encrypted traffic, an NGFW must act as a secure intermediary.

In practice:

  1. The client establishes a secure connection with the firewall.
  2. The firewall presents a trusted internal certificate.
  3. Traffic is decrypted, inspected by security engines, and evaluated against policies.
  4. The firewall re-encrypts the traffic and forwards it to the destination server.

From a user perspective, nothing changes.
From a security perspective, visibility is restored.

This enables:

  • real malware detection,
  • blocking phishing and malicious downloads,
  • inspection of application-layer attacks,
  • meaningful application and web filtering.

Why deploying NGFW without SSL Inspection is usually a mistake

Let’s be transparent:

If an organization invests in a Next Generation Firewall but does not plan SSL/TLS Inspection, the return on investment is severely reduced.

RealityImpact
Most traffic is encryptedFirewall sees only metadata
Modern threats use HTTPSAttacks remain invisible
NGFW licenses are expensiveSecurity engines are underused
Compliance and audits expect real inspectionSecurity posture looks good only on paper

This is not a configuration detail – it is a design decision.

How BOIT helps organizations deploy NGFW properly

At BOIT, we regularly work with organizations that already have an NGFW in place — but are unsure whether it actually protects their network.

Our approach is practical and transparent.

We start by analyzing real network traffic, not diagrams or assumptions.
Then we:

  • design a balanced SSL/TLS Inspection policy (not “decrypt everything blindly”),
  • define safe and compliant exclusions (banking, healthcare, critical services),
  • ensure the firewall has enough performance for decryption workloads,
  • integrate NGFW policies with identity systems (Active Directory / Entra ID),
  • deploy internal certificate infrastructure cleanly and safely,
  • test real-world attack scenarios, not just dashboards.

The result is not just a “configured firewall”, but measurable security improvement.

Who should consider this approach?

  • Organizations that already use NGFW but want to verify real effectiveness
  • Companies preparing for ISO 27001, TISAX, NIS2 or internal audits
  • IT teams that want control, visibility and operational clarity
  • Businesses that understand that modern security requires insight into encrypted traffic

Oskar Dyjach
Oskar Dyjach