Nikto
A practical guide to the classic open-source tool for web server vulnerability scanning and assessment.
Nikto is a widely used open-source web server scanner designed to identify potential security issues in web applications and configurations. Built for speed and coverage, Nikto checks for thousands of known vulnerabilities, outdated server components, dangerous files, misconfigurations, and default settings across HTTP/HTTPS services. It’s a foundational tool in web application assessments, valued for its simplicity, reliability, and wide plugin support.
Whether you're scanning an internal portal, auditing internet-facing assets, or running automated recon as part of a larger test, Nikto helps uncover risky exposures that attackers might exploit.
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What Nikto Does
Nikto scans web servers by sending crafted HTTP requests to enumerate known vulnerabilities and unsafe files. It detects outdated software versions, insecure options, missing security headers, and default content left behind by administrators. By parsing server responses, it builds a report of all identified issues, many of which could lead to information leakage, privilege escalation, or full compromise.
Nikto uses a large, actively maintained signature database to check for over 6,700 potentially dangerous files and programs, 1,200+ insecure software versions, and over 250 server misconfigurations.
Key Features of Nikto
Extensive Vulnerability Database
Continuously updated to check for thousands of known issues, including outdated servers, CMS flaws, and misconfigured options.
Wide Server Compatibility
Supports Apache, Nginx, Microsoft IIS, and other web server technologies.
SSL/TLS Support
Scans both HTTP and HTTPS services, including checks for expired certificates, insecure ciphers, and known SSL vulnerabilities.
Customizable Reports
Generates scan results in plain text, HTML, CSV, or XML formats for easy parsing and reporting.
Proxy and Authentication Support
Allows scanning through HTTP proxies and supports basic authentication to reach protected areas.
Evasion Techniques
Includes options to bypass basic security measures such as web application firewalls (WAFs) by encoding payloads or changing user-agent strings.
Plugin Architecture
Easily extended through plugins and test modules for specific applications or custom environments.
Advanced Use Cases
Web Application Security Audits
Run non-intrusive scans to identify outdated platforms, exposed configuration files, and known CMS issues.
Perimeter Asset Sweeps
Assess external-facing servers for low-hanging fruit and legacy configurations that could pose a risk.
Penetration Testing and Reconnaissance
Integrate with broader toolchains to supplement manual testing or recon phases.
Compliance Assessments
Support baseline security checks for compliance frameworks that require vulnerability scanning of web services.
CI/CD Pipeline Integration
Use Nikto in automated pipelines to scan newly deployed applications or staging environments for exposure risks.
Latest Updates
Recent improvements to Nikto include:
Enhanced plugin and scan database with new checks for CMS platforms and API vulnerabilities
Expanded SSL scanning capabilities with updated cipher and protocol checks
Improved performance on large web apps through optimized request handling
Refined output formatting for compatibility with other security tools and dashboards
Additional evasion and user-agent spoofing options for stealthier scans
Why It Matters
Web servers are frequent entry points for attackers, and misconfigurations or forgotten files can expose significant vulnerabilities. Nikto offers a fast, reliable way to surface these issues before they’re exploited. While it’s not a stealth scanner, Nikto is highly effective at uncovering real, actionable risks, making it an essential first-pass tool for web app assessments and security hygiene.
Requirements and Platform Support
Nikto runs on:
Linux
macOS
Windows (with Perl installed)
It requires:
Perl (v5.x)
Basic command-line usage familiarity
Internet access for updates and online scans (optional)
Nikto is open-source and freely available at https://github.com/sullo/nikto, with active community support, updateable scan databases, and documentation for plug-in development and integration.