FUNDAMENTALS OF COMPUTER

Detailed explanation-1: -Different antivirus programs use different “signatures” to identify viruses. The disadvantage of this detection method is that users are only protected from viruses that are detected by signatures in their most recent virus definition update, and not protected from new viruses (see “zero-day attack").

Detailed explanation-2: -The main weakness of virus signatures is in detection of new viruses. Another method of virus detection is the use of heuristics. In these systems, antivirus programs use algorithms to detect the behavior patterns that were found when a specific virus was tested by researchers.

Detailed explanation-3: -Signature-based antivirus is a type of security software that uses signatures to identify malware. Signatures are bits of code that are unique to a specific piece of malware. When signature-based antivirus software detects a piece of malware, it compares the signature to its database of known signatures.

Detailed explanation-4: -In the antivirus software, the virus signature is called a definition file or DAT file. Multiple viruses may have the same virus signature, which allows antivirus programs to detect multiple viruses when looking for a single virus signature.

Detailed explanation-5: -Most sophisticated antiviruses are not affordable for a regular internet user, and some offer security features for an extra cost. Another disadvantage of antivirus software is impact on system performance.