Using NDR (Network Detection and Response) to eliminate unknown network threats is one of its most powerful capabilities—particularly because traditional security tools (like firewalls and antivirus) rely heavily on known signatures and rules, whereas NDR solutions can detect novel, stealthy, and zero-day attacks.

What Are Unknown Network Threats?

"Unknown threats" refer to malicious activity that doesn’t match any known pattern, such as:

• Zero-day exploits

• Novel command-and-control (C2) methods

• Fileless malware

• Insider threats with no IOC trail

• Abnormal but low-and-slow attacks

• Use of legitimate tools (e.g., PowerShell, SMB) in unexpected ways

How NDR Detects Unknown Threats

Unlike signature-based tools, NDR detects based on behavior, context, and anomalies using several techniques:

1. Behavioral Baselines

NDR solutions build a profile of “normal” behavior for users, devices, workloads, and applications.

Then it flags:

• Unusual access times

• New or rare destinations

• Traffic volume spikes

• Device-to-device communication that hasn’t occurred before

Example: A backup server suddenly initiating outbound DNS tunneling = suspicious.

2. Anomaly Detection via Machine Learning

ML models learn patterns over time and detect subtle deviations that may indicate unknown threats.

Flags behaviors like:

• Unexpected lateral movement (e.g., desktop to finance server)

• Protocol misuse (e.g., HTTP over port 443)

• High-entropy domains (used in DGA attacks)

Example: Host starts beaconing to an IP with no known reputation, using uncommon protocol signatures.

3. Encrypted Traffic Analytics (ETA)

Even when payloads are encrypted (e.g., TLS 1.3), NDR platforms detects threats based on metadata and behavioral fingerprints.

Techniques include:

• JA3/JA3S fingerprinting

• Session duration, packet size, timing

• Identifying unusual encrypted sessions or traffic patterns

Example: Malware communicating with its C2 via HTTPS mimicking Google, but with suspicious JA3 fingerprint.

4. MITRE ATT&CK-Based Detection

NDR aligns behaviors to known adversary tactics, even when the specific tools or payloads are unknown.

Example:

• Suspicious remote desktop login + lateral SMB access → maps to MITRE techniques T1021.001 and T1021.002

• NDR sees the pattern, not the tool

5. Unmanaged / Rogue Device Detection

Unknown threats often come from rogue devices (e.g., Raspberry Pi on the network, infected IoT).

Network Detection and Response (NDR) identifies new devices and watches for:

• Abnormal communication patterns

• Passive MAC/IP profiling

• DNS anomalies from unknown sources

Example: IoT camera begins uploading large volumes of data to a foreign IP = alert.

6. Continuous Threat Hunting

• Security analysts can use NDR to:

  • Search for rare or first-seen behaviors

  • Trace connections from suspicious hosts

  • Link seemingly unrelated events into one threat chain

Proactive hunting uncovers threats before damage is done.

7. Automated Scoring and Prioritization

• Assigns threat scores based on severity, asset importance, and behavior

• Surfaces the highest-risk unknown threats first

• Enables quicker triage and response

Avoids wasting time chasing noise or benign anomalies.

Real-World Use Case

Threat: Zero-day ransomware uses SMB for lateral spread, no known signatures.

How NDR solutions helps:

1. Detects anomalous SMB traffic between devices that never communicated before

2. Flags large file transfers to external shares

3. Identifies repeat beaconing behavior to unlisted domains

4. Scores activity as high-risk, correlates across sessions

5. Alerts SOC and optionally auto-isolates affected device

Summary: How NDR Eliminates Unknown Threats

Bonus: Key Benefits

• Reduces dwell time for unknown threats

• Increases SOC visibility where EDR/AV can’t see

• Protects against advanced attacks using fileless or living-off-the-land techniques

• Strengthens cloud, IoT, and remote network defenses