What is a potential downside of signature-based scanners?

A potential downside of signature-based scanners is that they may miss new malware attacks. Signature-based detection relies on predefined patterns or "signatures" of known malware threats. When a new strain of malware is introduced—one that has not yet been analyzed and documented by security researchers—signature-based scanners are ill-equipped to detect it, as they do not recognize the new signature. This limitation makes these scanners vulnerable to zero-day attacks and other emerging threats that have not been cataloged in their databases.

In contrast, other options present scenarios that do not specifically highlight the inherent limitations of signature-based approaches. For example, while false positives can occur with various types of scanners, it is typically not a defining weakness of signature detection. Similarly, user permissions and real-time protection relate more to the functionality and configuration of security measures rather than the nature of signature-based scanning itself.