Why is a penetration test considered to be more thorough than vulnerability scan?

Vulnerability scanners perform much more than host discovery and port scanning - they also check service versions, configurations, and known CVEs against a comprehensive signature database.

A penetration test simulates a real attacker by actively exploiting discovered vulnerabilities to gain access or escalate privileges, demonstrating actual risk; a vulnerability scan only identifies and reports potential vulnerabilities without attempting exploitation, making penetration testing more thorough in validating real-world exposure.

This reverses the reality; penetration tests are typically performed by skilled human testers using manual techniques, while vulnerability scans are the predominantly automated process.

The comprehensiveness of tool vulnerability databases is not the defining distinction; the key difference is active exploitation versus passive identification of weaknesses.