What type of NIDS/NIPS is best suited to recognize zero-day attacks?

Anomaly-based intrusion detection systems (NIDS/NIPS) are particularly effective at recognizing zero-day attacks because they operate by establishing a baseline of normal behavior within the network or system. By monitoring traffic and activities against this baseline, any deviations or anomalies can be flagged as potentially malicious, even if they do not match known signatures of attacks.

Zero-day attacks exploit vulnerabilities that are not yet known to security professionals or for which no patches are available. Since signature-based systems rely on predefined patterns of known threats, they are ineffective against these new and unknown exploits. Anomaly-based systems, on the other hand, can alert to suspicious activity that deviates from what is considered normal, regardless of whether that specific behavior has been documented previously.

This ability to detect unusual patterns makes anomaly-based detection crucial for identifying zero-day vulnerabilities and attacks that may otherwise go unnoticed until after damage has been done.