Nikto is a widely recognized, open-source web server scanner that serves as a fundamental tool within the CompTIA PenTest+ curriculum, specifically regarding Vulnerability Discovery and Analysis. Written in Perl, Nikto is designed to perform comprehensive tests against web servers to identify known…Nikto is a widely recognized, open-source web server scanner that serves as a fundamental tool within the CompTIA PenTest+ curriculum, specifically regarding Vulnerability Discovery and Analysis. Written in Perl, Nikto is designed to perform comprehensive tests against web servers to identify known security vulnerabilities, misconfigurations, and outdated software. Unlike dynamic application security testing (DAST) tools that analyze application logic, Nikto focuses heavily on the web server infrastructure itself.
The scanner checks for over 6,700 potentially dangerous files and programs (such as default installation files, sample scripts, and backup files), scans for outdated server versions, and looks for version-specific problems on over 270 server types. It also analyzes server configuration items, such as the presence of multiple index files, HTTP server options, and missing security headers.
For a PenTest+ candidate, it is crucial to understand that Nikto is an 'aggressive' and 'noisy' scanner. It is not designed for stealth; its rapid succession of requests creates a distinct signature that is easily detected by Intrusion Detection Systems (IDS) and blocked by Web Application Firewalls (WAF). Consequently, it is best utilized during white-box testing or when assessing the reactivity of a target's monitoring systems. While it supports features like SSL scanning, proxy support, and evasion techniques (LibWhisker), it often generates false positives due to its reliance on database signatures. Therefore, a pentester must manually verify Nikto's findings to confirm actual exploitability. Output formats include XML, HTML, and CSV, facilitating integration into final penetration testing reports.
Nikto Web Scanner: Vulnerability Discovery and Analysis
What is Nikto? Nikto is an Open Source (GPL) web server scanner written in Perl. It performs comprehensive tests against web servers for multiple items, including over 6700 potentially dangerous files/programs, outdated versions of over 1250 servers, and version-specific problems on over 270 servers. It also checks for server configuration items such as the presence of multiple index files and HTTP server options, and will attempt to identify installed web servers and software.
Why is it Important? In the CompTIA PenTest+ curriculum, Nikto represents the standard for web-specific vulnerability scanning. Unlike general network scanners (like Nmap) or heavy vulnerability management platforms (like Nessus), Nikto is lightweight and specifically designed to find 'low-hanging fruit' on web servers, such as default scripts, unpatched server versions, and misconfigurations that lead to information disclosure.
How it Works Nikto operates by sending a large volume of specific HTTP requests to the target web server and analyzing the responses. It utilizes a database of known signatures to match against the server's response headers and body content. Key operational characteristics include: 1. Signature Based: It looks for known bad files (e.g., /admin/config.php). 2. Version Fingerprinting: It analyzes headers to determine if the server software (e.g., Apache, IIS) is outdated. 3. Configuration Checks: It checks for enabled methods (like PUT or DELETE) and directory indexing.
Basic Syntax The most basic command is: nikto -h <IP or Domain>. Other useful switches include: -p: Specify a port (default 80). -ssl: Force SSL mode. -Tuning: Specify the type of test (e.g., SQL Injection, File Upload). -o: Output file (supports txt, html, xml, csv).
Exam Tips: Answering Questions on Nikto web scanner To successfully answer PenTest+ questions regarding Nikto, remember these key concepts:
1. Identify the Scope: If a question asks about scanning a Web Server for CGI scripts, outdated software, or default files, Nikto is the primary answer choice.
2. The 'Noisy' Factor: Nikto is extremely noisy. It generates thousands of 404 errors in server logs very quickly. If a scenario asks for a stealthy scan or how to avoid tripping an IDS/IPS, a default Nikto scan is the wrong answer. Conversely, if a log shows thousands of rapid requests for random files, the answer is likely a web scanner like Nikto.
3. False Positives: Nikto is known for false positives, particularly regarding software versions. It checks banners, not actual patch levels. If a question asks about verifying results, the answer often involves manual verification or checking if a patch was backported.
4. Evasion Techniques: You may be asked how to reduce detection. Nikto uses the -evasion switch (incorporating LibWhisker techniques) to obfuscate URLs (e.g., using directory self-reference /./) to bypass basic IDS signatures.
5. Output Format: Questions may ask how to save the report for a developer. Nikto supports HTML and XML, which are standard formats for reporting.