Web Application Pentest Series: A Deep Dive Into Securing the Web

Because the internet has become an essential component of daily life, web apps are vital to businesses and society as a whole. Because of this dependence, bad actors find web apps to be easy targets. We will delve deeply into web application security using the OWASP Testing Guide in this first installment of the Web Application Pentest Series. This thorough process contributes to the security of your web apps.

This blog post will discuss the preliminary phases of pentesting, with an emphasis on information gathering under OWASP recommendations. It will also include real-world examples and a breakdown of test cases from a penetration testing process.

Why Web Application Pentesting Matters

Web applications can serve as entry points to internal networks and contain sensitive data and business logic. Data theft, vandalism, or system compromise are all possible outcomes of a breach. Pentesting is therefore a crucial component of every company's cybersecurity program. Pentesting makes a web application safer by finding flaws and vulnerabilities before attackers can take advantage of them.

The OWASP Testing Guide

A commonly accepted standard for web application security testing is the OWASP (Open Web Application Security Project) Testing Guide. It provides a thorough list of methods and checks for evaluating the security of online applications. Following version 4 of this guide, we will dissect each step as we move through the series, emphasizing critical test cases and providing real-world testing scenarios.

In addition to providing a summary of vulnerabilities, this guide also includes tools and real-world examples covering approximately 200–300 test cases. Testers may effectively safeguard online applications, find vulnerabilities, and rank remedies by adhering to OWASP's standardized methodology.

Phase 1: Information Gathering

Any penetration test starts with information collecting. Finding as much publicly accessible information as you can about the intended web application is crucial. This stage entails gathering information via open-source intelligence (OSINT), dissecting the architecture of web applications, and locating possible points of entry for additional testing.

Test Case Breakdown (Information Gathering)

Here’s a detailed breakdown of the key test cases involved in this phase using the OWASP Test Case Spreadsheet:

1.1 Conduct Search Engine Discovery

• OWASP ID: WSTG-INFO-01
• Objective: Identify sensitive design and configuration information about the web application. This could include discovering internal systems, old versions, or files that should not be exposed.
• Tools: Google Hacking, Shodan, Recon-ng
• OWASP Top 10: N/A
• Steps:
  • Use advanced Google search operators to find exposed documents, directories, or login portals.
  • Run Shodan to detect any exposed devices or servers related to the web application.

1.2 Fingerprint Web Server

• OWASP ID: WSTG-INFO-02
• Objective: Determine the version and type of web server used. Fingerprinting helps identify known vulnerabilities that can be exploited.
• Tools: Whatweb, Nikto
• OWASP Top 10: A5 (Security Misconfiguration)
• Steps:
  • Use Whatweb to gather server details such as software, versions, and plugins.
  • Run Nikto to identify vulnerabilities and misconfigurations.

1.3 Identify Application Entry Points

• OWASP ID: WSTG-INFO-06
• Objective: Identify entry points in the application that accept user input, such as login forms or search bars. This helps in testing for potential injection flaws and other exploits.
• Tools: Burpsuite/ZAP, OWASP ASD
• OWASP Top 10: A1 (Injection), A2 (Broken Authentication)
• Steps:
  • Intercept and analyze traffic using Burpsuite.
  • Identify hidden form fields, headers, and parameters that could be manipulated.

Manual vs Automated Testing

Although pentesting procedures can be sped up with the use of tools like Burpsuite, Nikto, and Whatweb, these technologies should be used in addition to manual testing. Large-scale scans are best performed by automated techniques, although human labor frequently reveals subtleties and logical errors that automated technologies may overlook. Automated scanners could miss vulnerabilities that can be found by manually examining the application's response to SQL injection attempts or business logic tampering.

Comprehensive penetration testing requires an appropriate ratio of automated tools to manual testing.

Real-World Example: Fingerprinting a Web Server

Here’s an example of fingerprinting a web server using Whatweb and Nikto:

• Step 1: Run Whatweb against the target URL.
  • Command: whatweb <target-url>
  • Output: Information about the server, framework, and plugins being used, such as Apache or Nginx.
• Step 2: Use Nikto to check for vulnerabilities in the discovered web server.
  • Command: nikto -h <target-url>
  • Output: List of misconfigurations, security flaws, and outdated components.

By analyzing these outputs, you can determine if the server is vulnerable to known exploits, and prioritize the next steps in your pentest.

Conclusion

You can be sure you've covered all the bases when it comes to spotting vulnerabilities in a web application by adhering to the OWASP Testing Guide. Collecting data is only the first step. We will delve deeper into pentesting in the next sections of the course, covering everything from input validation to taking advantage of logical errors.

Call to Action

Keep checking back for future postings in the Web Application Pentest Series, where we'll discuss testing techniques, real-world case studies, and vulnerabilities in greater detail. Check out my earlier blog entries and other resources on the Sarsolutionz Blog if you're curious to learn more or if you need assistance with the security of your web application.

Happy Pentesting!