How does a signature-based IDS operate?

A signature-based Intrusion Detection System (IDS) operates by monitoring network traffic and analyzing it against a database of known attack patterns or signatures. This method relies on the recognition of specific patterns that have been identified as malicious behavior in the past. When the system detects a match between incoming data and any existing signatures, it triggers an alert, indicating a potential intrusion or attack.

This approach is particularly effective for identifying well-documented threats because it can quickly and accurately detect known vulnerabilities. However, it may struggle with new or evolving threats that do not yet have defined signatures, which limits its effectiveness in scenarios like zero-day attacks.

The other options do not accurately describe the function of a signature-based IDS. Creating a firewall relates more to blocking unauthorized access to networks rather than detecting specific threats. Performing regular backups concerns data protection rather than intrusion detection, and encrypting sensitive data focuses on securing information in transit rather than identifying malicious activities.