A tutorial on how to use the Gospider web crawler.
Bug bounty hunters and penetration testers use web crawlers (or web spiders) to gather critical information about web applications and sites. This automated exploration helps identify potential vulnerabilities and areas for further manual testing. Here’s how web crawling can be utilized effectively:
1. Mapping the Application
Identify Hidden Paths: Crawlers reveal URLs and paths that are not directly linked on the website, potentially exposing hidden pages or admin interfaces.
Directory Structure: Understanding the directory structure helps testers see how the application is organized and where sensitive files might be located.
Parameter Discovery: Crawlers can uncover GET and POST parameters used in forms and URLs, aiding in the identification of areas to test for injection flaws.
2. Finding Vulnerabilities
Sensitive Information Exposure: Crawlers might find files with sensitive information (e.g., .git, .svn, backup files, or configuration files) that are accessible.
Security Misconfigurations: Unprotected directories or misconfigured security headers can be identified through the information gathered.
Old or Deprecated Files: Crawlers may find old versions of scripts or pages that could have known vulnerabilities.
3. Automated Scanning and Enumeration
Content Enumeration: Crawlers can enumerate subdomains, directories, and file types to be further tested for vulnerabilities.
Error Messages: By requesting various resources, crawlers might trigger error messages that reveal information about the server or software stack.
4. Automation of Repetitive Tasks
Input Fuzzing: Automating input into discovered forms can reveal common vulnerabilities like SQL Injection or Cross-Site Scripting (XSS).
Automated Vulnerability Scanning: Integrating crawlers with scanners can automate the process of detecting known vulnerabilities across the web app.
5. Gaining Insights for Manual Testing
Link Analysis: Analyzing links and their relationships provides insights into the site's functionality and navigation flow, aiding in manual testing strategies.
Understanding Functionality: Crawlers help testers understand how different parts of the application are interconnected and how they function together, guiding deeper manual tests.
6. Reporting and Compliance
Comprehensive Reports: Data from crawlers can be used to generate detailed reports showing all the discovered URLs, parameters, and potential issues, which are valuable for both remediation and compliance documentation.