Gavin owns a white-hat firm and is performing a website security audit.

Comprehensive and Detailed Explanation:

Nikto is an open-source web server scanner that:

Checks for common vulnerabilities

Detects outdated software versions

Flags insecure configurations and files

It is widely used for quick and comprehensive web vulnerability assessments.

From CEH v13 Courseware:

Module 10: Web Application Hacking → Web Vulnerability Scanning Tools