The Beginner’s Guide to Bug Bounty Hunting: Finding and Reporting Easy Bugs

Bug bounty hunting is an exciting and rewarding field that allows security enthusiasts to help secure applications while earning rewards. However, starting out can be overwhelming, especially when you’re unsure where to begin or what to look for. In this comprehensive guide, we’ll explore the easiest bugs to find in bug bounty programs, where to look, what tools to use, where to practice, and how to report your findings effectively.

1. Missing Security Headers

• What Are They?
  Security headers are HTTP response headers that help protect web applications from various attacks by instructing browsers on how to handle content. Common security headers include:
  • Content Security Policy (CSP): Mitigates XSS attacks by controlling which resources can be loaded.
  • Strict-Transport-Security (HSTS): Forces browsers to use HTTPS, preventing man-in-the-middle attacks.
  • X-Frame-Options: Prevents clickjacking by controlling if a page can be embedded in an iframe.
  • X-Content-Type-Options: Stops browsers from MIME-sniffing, preventing certain types of XSS.
• Where to Look?
  Analyze the HTTP response headers of web pages. You can inspect these headers using browser developer tools or by running automated scans.
• How to Find?
  Use tools like SecurityHeaders.io or Mozilla Observatory to quickly check for missing headers.
• Example Report:
  “The Strict-Transport-Security header is missing, allowing the possibility of man-in-the-middle attacks if an attacker can intercept traffic.”

2. Open Redirects

• What Are They?
  An open redirect occurs when a web application allows redirection to an external URL without proper validation, which attackers can exploit to redirect users to malicious sites.
• Where to Look?
  Search for URL parameters that seem to control redirects, such as redirect, url, next, or returnTo.
• How to Find?
  Manipulate the parameter by replacing its value with an external URL and observe if the application redirects you. For example: https://example.com/login?redirect=http://evil.com
• Example Report:
  “The application allows open redirection through the redirect parameter, which could be exploited to redirect users to malicious sites.”

3. Information Disclosure

• What Is It?
  Information disclosure refers to unintentionally revealing sensitive information such as stack traces, debug information, or configuration files.
• Where to Look?
  Trigger errors by entering unexpected input, such as SQL injection attempts (' OR 1=1 --), or by accessing non-existent pages.
• How to Find?
  Review the error messages returned by the server. Look for details that reveal the server software, database, file paths, or internal IP addresses.
• Example Report:
  “The application exposes detailed error messages that disclose server information, which could aid attackers in exploiting the system.”

4. Cross-Site Scripting (XSS)

• What Is It?
  XSS vulnerabilities occur when an application allows users to inject malicious scripts into web pages viewed by others. There are three main types: stored, reflected, and DOM-based XSS.
• Where to Look?
  Focus on user input fields, query parameters, and forms where input is reflected back on the page. Also, consider any place where user-generated content is displayed.
• How to Find?
  Test inputs with simple scripts like: <script>alert('XSS')</script> If the script executes, the site is vulnerable to XSS.
• Example Report:
  “The input field on the /contact page is vulnerable to reflected XSS, allowing attackers to inject and execute arbitrary scripts.”

5. Default Credentials or Insecure Authentication

• What Are They?
  Some systems are deployed with default credentials (e.g., admin/admin) or have weak authentication mechanisms, making it easy for attackers to gain unauthorized access.
• Where to Look?
  Identify login portals, admin panels, or any other authentication mechanisms.
• How to Find?
  Attempt to log in using common default credentials or simple passwords like admin/admin, password, etc. You can also check for brute-force protection mechanisms.
• Example Report:
  “The admin panel at /admin is accessible using the default credentials admin:admin, which could allow unauthorized access to sensitive data.”

6. IDOR (Insecure Direct Object Reference)

• What Is It?
  IDOR vulnerabilities occur when an application exposes references to internal objects like database records, files, or directories, and does not properly enforce access controls.
• Where to Look?
  Examine URLs, API endpoints, or form data that reference IDs, filenames, or other object identifiers.
• How to Find?
  Try manipulating the identifier to access objects that should belong to other users. For example: https://example.com/user/12345/profile Change 12345 to another user’s ID.
• Example Report:
  “The API endpoint /user/[user_id]/profile is vulnerable to IDOR, allowing unauthorized access to other users’ profiles.”

Where to Start?

• 1. Platforms for Bug Bounty Hunting:
  • HackerOne: One of the largest bug bounty platforms with a wide variety of programs.
  • Bugcrowd: Another popular platform that offers a mix of private and public programs.
  • Synack: Requires an application and a background check but offers higher rewards.
  • Open Bug Bounty: A more accessible platform for beginners with a focus on responsible disclosure.
• 2. Free Labs to Practice:
  • PortSwigger’s Web Security Academy: Offers free labs covering a wide range of vulnerabilities.
  • Hack The Box: Provides challenges and machines to practice various vulnerabilities.
  • OWASP Juice Shop: A deliberately vulnerable web application for learning about security.
• 3. Free Resources:
  • OWASP Top Ten: A list of the top ten most critical web application security risks, which is a must-read for bug hunters.
  • HackerOne Hacktivity: Browse disclosed reports to learn from other hackers.
  • Blogs and Write-ups: Read blogs from experienced hunters like NahamSec, Stök, and LiveOverflow.

Where to Report?

• 1. Bug Bounty Platforms: If you’re participating in a program on platforms like HackerOne or Bugcrowd, submit your reports there.
• 2. Responsible Disclosure Programs: Many organizations have dedicated security pages where you can report vulnerabilities responsibly.
• 3. Direct Contact: If no official program exists, consider reaching out to the company directly via email or social media.

What Tools to Use?

• 1. Burp Suite: A comprehensive tool for web vulnerability scanning and exploitation.
• 2. OWASP ZAP: An open-source alternative to Burp Suite for scanning and exploiting vulnerabilities.
• 3. Postman: Useful for testing API endpoints.
• 4. Nmap: Network scanning tool to identify open ports and services.
• 5. Nikto: A web server scanner to find known vulnerabilities.

Conclusion

Starting in bug bounty hunting doesn’t have to be daunting. By focusing on the easier bugs like missing security headers, open redirects, and XSS, you can quickly build confidence and start earning bounties. With the right tools, resources, and practice, you’ll be well on your way to finding and reporting vulnerabilities effectively.

Happy Hunting!