Insider threats represent one of the most complex and damaging cybersecurity challenges organizations face today. Whether they stem from malicious intent, negligence, or compromised credentials, insiders have the access and knowledge to cause serious harm. Traditional security tools often fall short in identifying these threats due to their reliance on static rules or their inability to correlate user behavior with network activity.

This is where Network Detection and Response (NDR) plays a vital role. By providing deep, behavioral insight into network traffic, NDR helps organizations identify and mitigate insider threats in real-time. In this article, we’ll explore how NDR strengthens insider threat detection and prevention, the unique capabilities it brings to the table, and how it complements other cybersecurity tools.

Understanding Insider Threats

Types of Insider Threats

Insider threats can be broadly categorized into three main types:

1. Malicious Insiders – Employees or contractors who intentionally steal, leak, or sabotage data for personal, financial, or ideological reasons.
2. Negligent Insiders – Well-meaning individuals who unintentionally compromise security through careless actions like misconfigurations or falling for phishing attacks.
3. Compromised Insiders – Legitimate users whose accounts or devices have been hijacked by external actors.

Each type presents different indicators and challenges, making detection a non-trivial task—especially when the insider is using legitimate credentials and tools.

The Limitations of Traditional Security Tools

SIEMs, firewalls, and endpoint detection solutions are crucial components of a security stack, but they have limitations when it comes to insider threats:

• SIEMs often rely on predefined rules and may not detect subtle behavioral anomalies.
• EDRs are endpoint-focused and may miss threats that traverse the network invisibly.
• Firewalls enforce perimeter controls but are blind to lateral movement inside the network.

Insider threats often operate within the boundaries of normal user behavior—making traditional tools blind to the deviation unless there’s a specific signature or alert.

How NDR Enhances Insider Threat Detection

NDR offers several unique advantages that make it particularly effective in combating insider threats:

1. Behavioral Analytics and Baselines

NDR solutions use machine learning and AI to establish behavioral baselines for users, devices, and applications. By continuously monitoring network traffic, NDR identifies anomalies such as:

• Unusual file transfers to external servers
• Access to sensitive data at odd hours
• Lateral movement within the network without justification
• Sudden spikes in data exfiltration

These behaviors often indicate insider activity that is either malicious or indicative of a compromised account.

2. Visibility into East-West Traffic

Unlike traditional perimeter-focused tools, NDR monitors internal traffic (east-west), which is critical for spotting lateral movement and privilege escalation. Insider threats often move laterally to gather more data or access higher-value targets.

NDR can detect:

• Access to systems that are outside a user’s normal scope
• Connections between devices that don’t usually communicate
• Unusual use of administrative privileges

3. Encrypted Traffic Analysis

Many insider threats hide their activity within encrypted channels. Modern NDR platforms can analyze encrypted traffic metadata without decryption, spotting anomalies in session behavior, duration, volume, and patterns.

This enables detection of:

• Encrypted exfiltration of data
• C2 (command-and-control) communications in encrypted channels
• Unauthorized use of secure protocols

4. Threat Hunting and Incident Response

NDR supports proactive threat hunting by giving analysts access to historical and real-time traffic data. Security teams can pivot on indicators like IP addresses, domains, or file hashes to trace insider activity across the network.

During an investigation, NDR can:

• Reconstruct sessions to analyze what was done
• Map user behavior over time
• Correlate suspicious events with device and user identities

Real-World Use Case: Catching a Malicious Insider

Consider a scenario where a disgruntled employee plans to steal intellectual property. They start accessing systems they normally don’t use and download large volumes of data during off-hours. They then transfer this data to an external server over an encrypted channel.

An NDR solution detects:

• Abnormal access patterns
• Data movement inconsistent with previous behavior
• Use of an unusual endpoint
• A new and untrusted external destination

All of these indicators are flagged and correlated, alerting security teams before the data exfiltration completes. Without NDR, this behavior could go unnoticed until it’s too late.

NDR and User Entity Behavior Analytics (UEBA)

While UEBA platforms focus on user behavior, combining UEBA with NDR provides a richer picture. UEBA might flag unusual login times, while NDR identifies where that user goes on the network and what they’re accessing.

This combined visibility enhances:

• Contextual understanding of threats
• Confidence in detections
• Faster and more accurate response

Best Practices for Using NDR Against Insider Threats

To maximize the value of NDR for insider threat detection:

1. Integrate with SIEM and SOAR platforms – Streamline alerts and automate response workflows.
2. Establish clear baselines – Customize baselines per user group and refine them over time.
3. Conduct regular threat hunting exercises – Use NDR data to look for dormant or slow-moving threats.
4. Train analysts on behavioral signals – Help teams distinguish between false positives and real risks.
5. Apply role-based access monitoring – Ensure that users access only what they need.

Conclusion

Insider threats are notoriously hard to detect, but Network Detection and Response offers a new line of defense. By providing deep behavioral analysis, visibility into lateral movement, and real-time anomaly detection, NDR equips organizations with the tools needed to uncover and mitigate threats from within.

As cyber threats evolve, organizations must move beyond perimeter-focused defenses. Integrating NDR into your cybersecurity strategy is not just a proactive step—it’s a necessary one for securing your organization from the inside out.