SSL Inspection in NDR: Unlocking Threats Hidden in Encrypted Traffic

June 13 • 3:01 pm

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Did you know that more than 90% of web traffic is now encrypted?1

Encryption makes online security better but creates a major blind spot for security teams. Cybersecurity analysts believe that over 90% of malware can hide in these encrypted channels and bypass traditional security measures.

Almost every website today uses HTTPS to encrypt data between a user’s browser and the site. This encryption protects legitimate traffic but also hides potential threats. Traditional threat detection methods miss much of this traffic. SSL inspection in NDR (Network Detection and Response) has become vital for organizations to track encrypted traffic.

Deep SSL inspection lets security systems decrypt and check encrypted HTTPS traffic immediately. This helps detect and block hidden malicious activities. On top of that, it gives organizations the ability to enforce compliance rules and stop data leaks. Security teams can substantially improve their visibility over encrypted traffic by using deep session inspection in NDR solutions. This makes essential security features like anti-virus scanning and malware detection work much better.

Why Is Encrypted Traffic a Security Blind Spot?

Organizations face a growing security challenge from encrypted traffic today. Cybercriminals exploit this blind spot more frequently, and network defense teams must understand these mechanisms.

Over 90% of Web Traffic is SSL Encrypted

The digital world has changed drastically over the last several years. Google’s data shows encrypted web traffic grew from 55% in 2017 to about 95% today.1

Almost all internet communications now flow through secure channels. Cisco’s Cognitive Intelligence tells us that 82% of HTTP/HTTPS traffic runs encrypted. This creates a massive volume of network activity that needs specialized inspection.

Security teams face their biggest problem – most network traffic moves through channels built to prevent examination. Our team at Fidelis sees this trend picking up speed in companies of all sizes, as SSL/TLS protocols become standard practice.

How Encrypted Channels Hide Malware Payloads

Cybercriminals have adapted their methods to utilize encryption as a way to hide. Bad actors know that encryption protects legitimate communications and shields their malicious activities equally well.

Common attack techniques include:

Hiding command and control communications behind encryption Concealing malware delivery through trusted ports and protocols Using SSL/TLS to mask data exfiltration activities Embedding threats in encrypted web sessions Banking trojans like IcedID utilize SSL/TLS to send stolen data. Traditional detection methods cannot spot these threats.

Why firewalls and traditional IDS/IPS struggle with SSL/TLS traffic

Standard security tools hit major roadblocks with encrypted traffic. The National Institute of Standards and Technology (NIST) states, “Network-based IDPSs cannot detect attacks within encrypted network traffic, including virtual private network (VPN) connections, HTTP over SSL (HTTPS), and SSH sessions”.

These tools face three major limitations when dealing with encrypted traffic:

Performance degradation during decryption

Traditional firewalls and intrusion prevention systems struggle to maintain performance when tasked with decrypting and inspecting SSL/TLS traffic. The process is resource-intensive, often slowing down traffic inspection or causing latency. Security teams are left with a difficult trade-off—enable full inspection and risk degrading the user experience, or prioritize speed and let encrypted threats slip through.

Limited support for modern encryption protocols

Many legacy security tools are not designed to keep pace with the rapid evolution of encryption standards. As protocols like TLS 1.3 and modern cipher suites become more common, outdated security appliances either fail to inspect this traffic or break connections altogether. This creates blind spots that attackers can exploit with ease.

Insufficient processing capacity for encrypted traffic

Inspecting encrypted traffic requires far more processing power than handling unencrypted data. Most traditional tools weren’t built for the computational demands of decryption and re-encryption at scale. This leads to dropped packets, missed threats, or the outright bypassing of encrypted flows to maintain uptime—compromising both detection capability and overall network security.

Our NDR solution includes deep SSL inspection capabilities. This helps organizations solve these blind spots without sacrificing network performance or security effectiveness.

Why SSL Inspection is Essential for NDR Cybersecurity

Network security teams hit a wall when their monitoring tools can’t handle encrypted traffic. Our team at Fidelis has seen SSL inspection become the life-blood of Network Detection and Response (NDR) solutions. Let me explain why this feature matters so much in today’s cybersecurity landscape.

Deep Packet Inspection vs. Deep SSL Inspection

Deep packet inspection (DPI) looks at header and payload information of network packets. This gives security teams a detailed view of network traffic. All the same, encrypted communications pose a real challenge. Standard DPI only works with unencrypted traffic, which creates major blind spots as encryption becomes more common.

Deep SSL inspection takes security to the next level. It goes beyond simple packet inspection by decrypting, analyzing, and re-encrypting traffic. Security systems can then look at encrypted content while maintaining protection. Our NDR solutions use a managed interception process to see what would normally stay hidden.

Detecting Phishing and Malware in Encrypted Sessions

Encrypted channels have turned into perfect hiding spots for advanced phishing campaigns and malware distribution. Cybercriminals use SSL/TLS to hide phishing links and malicious payloads. They know standard security tools struggle to spot these threats.
Our NDR solution uses deep SSL inspection to find:

Suspicious certificate issues like self-signed or expired certificates
Malicious command and control messages hidden in encrypted traffic
Data theft attempts masked as normal sessions
Phishing links buried in encrypted emails and web sessions

Secure What Encryption Hides

Reveal threats hidden inside SSL with Fidelis.

How SSL/TLS inspection boosts NDR’s detection and response accuracy

NDR tools lose most of their power without SSL inspection. Studies show security tools become five times more effective when they can decrypt traffic before analysis.

SSL/TLS inspection improves threat detection in all network traffic flows—ingress-egress, north-south, and east-west patterns. This visibility helps our solutions catch advanced evasion techniques. These include traffic over non-standard ports, protocol tunneling, and suspicious patterns from remote access tools.

Organizations need deep SSL inspection to protect their networks. It’s not just an upgrade—it’s essential. Security teams that add this capability to their NDR systems can spot threats that would otherwise slip through unnoticed.

What Are the Key Challenges of SSL Inspection in NDR?

While SSL inspection significantly enhances network visibility, it also introduces several technical and operational challenges that security teams must address for successful deployment.

Performance and Scalability

Decrypting encrypted traffic is a resource-intensive process. It requires considerable processing power, which can slow down network performance, especially in high-throughput environments. Many legacy tools struggle to keep up, forcing teams to choose between full inspection and maintaining performance. This trade-off can compromise both detection capability and user experience.

Certificate Pinning and Exception Handling

Modern applications often use certificate pinning—a method that ties specific certificates to a domain or service. This can break connections when SSL inspection in NDR tries to intercept and resign the certificates. Organizations need to manage such exceptions carefully, especially in environments where sensitive categories like healthcare or financial services are in play. In such cases, security teams may need to selectively bypass SSL inspection for specific trusted domains or sensitive data flows. Intelligent exception handling becomes critical to avoid service disruptions without weakening security posture.

Regulatory and Privacy Concerns

Decrypting certain types of traffic can raise compliance risks. Regulations like GDPR and others impose strict controls on how personal data is handled, making it crucial to strike a balance between visibility and privacy. Security teams must ensure that inspection practices align with applicable laws and data protection requirements.

User Experience and Latency

When SSL inspection isn’t optimized, users may notice slower application performance, delays in loading content, or disruptions in real-time services like voice or video. These issues can frustrate users and impact productivity if not addressed proactively.

How Does Fidelis Elevate® Solve SSL Inspection Challenges?

Fidelis Elevate® stands out by solving the complex challenges of SSL inspection. The solution uses a layered approach that balances security with what organizations need. Security teams no longer face traditional trade-offs when they implement SSL inspection in their Network Detection and Response strategies.

Expandable SSL inspection without performance compromise

Most solutions make you choose between security and speed. Fidelis Elevate® gives you full visibility into encrypted traffic without slowing down performance. Our mutually beneficial alliance with A10 Networks has created a specialized architecture that handles CPU-intensive SSL/TLS decryption separately. This lets us inspect traffic on all TCP ports and protocols without the slowdowns that affect other security tools. The traffic then gets re-encrypted and sent to its destination. You retain control over security and speed even when traffic volumes are high.

Smart exception handling and certificate management automation

Certificate pinning and privacy concerns are no longer roadblocks with Fidelis Elevate®. The solution comes with sophisticated bypass features that automatically identify sensitive encrypted traffic—like financial services and healthcare data—and excludes it from decryption. The certificate management system handles multiple ACME clients on different platforms automatically. This cuts down administrative work and removes human error from certificate lifecycle management.

Deep Session Inspection to spot encrypted threats faster

The heart of our solution is our proprietary Deep Session Inspection® (DSI) technology that:

Rebuilds network traffic into complete application sessions
Looks at the full context of communications beyond single packets
Gets critical metadata from each protocol layer
Decodes application protocols to find potential threats
This session-based method provides much more context than packet-based inspection, and catches threats that other solutions miss.

Immediate visibility in high-speed environments

Fidelis Elevate® sends confirmed, context-rich alerts the moment it detects threats. Security teams can solve problems in minutes instead of days. The solution analyzes network traffic on all ports and protocols to eliminate blind spots from encrypted traffic. Yes, it is possible to see both inbound and outbound encrypted communications clearly. This ensures detailed protection of your resilient infrastructure, whatever the speed or volume.

Conclusion: Is SSL Inspection the Missing Link in Your NDR Strategy?

Encrypted traffic was once a symbol of secure communication—but today, it’s also become a hiding place for threats. This shift has transformed how organizations must think about network security.

Without SSL inspection, most traditional security tools can’t see what’s moving through encrypted channels. Cybercriminals take advantage of this blind spot to evade detection and carry out attacks silently. SSL inspection in NDR restores visibility, giving security teams the clarity they need to detect and stop these threats.

Fidelis Network® is built to eliminate the complexities that make SSL inspection difficult to implement. With our approach, organizations no longer have to choose between performance and protection. We provide the flexibility to inspect encrypted traffic at scale—without slowing things down.

As the cybersecurity landscape continues to evolve, one thing remains constant: security tools are only as effective as the visibility they offer. If encrypted traffic goes unchecked, so do the threats it can conceal.

At Fidelis Security, we understand the operational and compliance challenges involved. That’s why our NDR solution is designed to simplify SSL inspection—so your team can focus on detecting threats, not managing complexity.

In today’s threat environment, SSL inspection isn’t an upgrade. It’s a necessity. And it may just be the difference between catching a threat in time—or not at all.

Expose Threats in Encrypted Traffic

See how Fidelis NDR decodes what others miss.

Citations:

^Google’s HTTPS Transparency Report

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