Here’s What Actually Happens When Antivirus Software Scans Your PC

Antivirus uses signature matching, heuristic analysis, and sandboxing. Signature matching compares file hashes against a database of known malware. Heuristic analysis looks for suspicious code patterns. Sandboxing runs the file in an isolated environment to observe behavior.

Traditional antivirus struggles with zero-day threats because no signature exists yet. However, modern antivirus uses heuristic and behavioral analysis to flag unknown suspicious files. Some also use cloud-based AI models to predict and block zero-day exploits.

Yes, but usually minimally. Active scans typically use 2-5% of CPU. Modern antivirus is optimized to run scans during idle times. Real-time protection has negligible impact on everyday tasks.

Most antivirus vendors update signature databases every 1-2 hours. Some, like Microsoft Defender, update continuously via cloud connections. You can manually check for updates in the software settings.

A false positive occurs when antivirus incorrectly flags a safe file as malicious. Industry benchmarks show false positive rates around 0.1%. Vendors often allow users to whitelist trusted files.