Final answer:
Signature-based scanning is a malware detection method that compares files' content against a database of known malware signatures. It is reliable for known threats but can be less effective for new or modified malware. Regular updates to signature databases are necessary to maintain effectiveness.
Step-by-step explanation:
Signature-based scanning detects malware by comparing a file's content with known malware signatures in a signature database. This method involves an anti-malware software checking the contents of a computer file to a vast database of malware signatures — unique strings of data or characteristics that are specific to known malicious software. When the anti-malware software encounters a file that contains the data corresponding to a known malware signature, it flags it as potential malware and typically takes action, such as quarantining the file or removing the threat.
Signature-based scanning is a traditional method of detection that provides reliability when dealing with known threats. However, it can be less effective against new, unknown, or modified malware, which might not yet have signatures in the database. This is why signature databases must be frequently updated, ensuring they can more effectively identify and stop newly emerging malware.