A recent web application security assessment offered valuable insights into the challenges and responsibilities that come with safeguarding online applications. By following the OWASP Testing Guide as a foundational framework, the assessment systematically uncovered vulnerabilities that could affect data integrity, user privacy, and system stability. With the help of industry-standard tools and methodologies, this assessment went beyond identifying vulnerabilities to connect each issue with its potential impact in a real-world business context.

In this blog, we’ll explore the techniques, methods, and the key findings that illustrate the critical importance of securing web applications.

Why Follow the OWASP Guide?

Using the OWASP Guide as a framework provided a comprehensive, structured approach for the assessment. It ensured that commonly exploited issues, as well as more nuanced weaknesses, were thoroughly tested. This guide, particularly the OWASP Top 10 vulnerabilities, directed the assessment's focus toward high-impact areas such as injection flaws, security misconfigurations, and access control weaknesses.

For those interested, here are links to OWASP’s resources that correspond with the vulnerabilities encountered:

• Path Traversal Vulnerability
• JSON Web Token Cheat Sheet
• Mass Assignment
• IDOR
• XSS Vulnerabilities

Key Findings and Insights

Each vulnerability presented unique lessons in understanding its impact on the application and the business context.

1. Path Traversal to Access Sensitive Files

The assessment revealed a path traversal vulnerability that allowed access to unintended files. This discovery emphasized the importance of securely coding file handling and input validation, showing how a seemingly small error could lead to unauthorized data exposure.

2. Weaknesses in JWT Handling and Token Management

Testing JWT handling uncovered multiple weaknesses:

• Weak Secret Key: Cracking the JWT secret made it possible to impersonate users and alter tokens, underscoring the importance of using complex, randomized secrets.
• Token Expiry Manipulation: Manipulating the exp field extended token lifespans, highlighting the need for server-side token validation to enforce expiration.

These flaws illustrate the critical role of strong JWT management in securing user sessions, particularly for applications handling sensitive data.

3. Mass Assignment in User Role Control

Through a mass assignment vulnerability, the assessment team could escalate privileges by adding unauthorized fields during registration. This issue highlighted the importance of back-end validation, especially in enforcing role-based access controls (RBAC) to prevent unauthorized privilege escalation.

4. Reflected Cross-Site Scripting (XSS) Causing Denial of Service (DoS)

Injecting malicious JavaScript in specific fields triggered a DoS condition, with persistent errors disrupting admin views. This vulnerability illustrated how XSS attacks could extend beyond data exposure, affecting system functionality and usability. Proper input validation, especially for user-controlled fields, is essential for mitigating XSS risks.

5. User Enumeration via Password Reset

The application allowed enumeration of registered users through error messaging in the password reset function. This vulnerability reminded the assessment team of the need to handle error responses carefully, as these messages can inadvertently reveal sensitive user information and lead to targeted attacks.

6. Predictable Application IDs Enabling IDOR Exploits

Predictable patterns in application IDs allowed unauthorized access to other users’ data—an insecure direct object reference (IDOR) vulnerability. Burp Suite’s Intruder made testing these patterns efficient, reinforcing the importance of generating randomized, unique identifiers for sensitive records.

Understanding Vulnerabilities in a Business Context

This assessment underscored the importance of viewing vulnerabilities not only as technical issues but as real-world risks. By connecting each finding with its potential business impact—whether related to user trust, data privacy, or application reliability—this approach added meaningful context to each vulnerability. For example, while IDOR might appear technically minor, its business implications could be significant if unauthorized access to sensitive user data is possible.

Understanding these vulnerabilities in a business context enhances reporting clarity and helps decision-makers prioritize remediation based on real-world risk.

Conclusion

This assessment reinforced that securing web applications requires both technical skill and an understanding of real-world impacts. Each vulnerability, from weak tokens to IDOR issues, underscored the importance of a layered approach to security. By following a structured framework like the OWASP guide and using specialized testing approaches, this assessment journey has built a strong foundation for future security work.

Looking at security through both a technical and business lens ensures that the work goes beyond fixing issues and contributes to a stronger, more resilient application landscape overall.