Introduction

Web application penetration testing is a critical component of any security program. This checklist provides a comprehensive guide to testing web applications for vulnerabilities in 2026.

Pre-Engagement

Before beginning any penetration test, ensure you have:

• Written authorization from the application owner
• Defined scope and rules of engagement
• Emergency contact information
• Backup and rollback procedures

Information Gathering

Passive Reconnaissance

• WHOIS lookups
• DNS enumeration
• Subdomain discovery
• Technology fingerprinting
• Search engine dorking

Active Reconnaissance

• Port scanning
• Service enumeration
• Directory brute-forcing
• Parameter discovery

Authentication Testing

• Test for default credentials
• Check password policy enforcement
• Test account lockout mechanisms
• Verify multi-factor authentication
• Test session management
• Check for credential enumeration

Authorization Testing

• Test for privilege escalation
• Check for IDOR vulnerabilities
• Verify access controls
• Test for path traversal

Input Validation

SQL Injection

' OR '1'='1
" OR ""="
' UNION SELECT NULL--

Cross-Site Scripting (XSS)

<script>alert('XSS')</script>
<img src=x onerror=alert('XSS')>

Command Injection

; ls -la
| cat /etc/passwd

Business Logic Testing

• Test for race conditions
• Check for workflow bypasses
• Verify pricing and payment logic
• Test for quantity manipulation

API Security

• Test for broken object level authorization
• Check for excessive data exposure
• Verify rate limiting
• Test for mass assignment vulnerabilities

Reporting

Document all findings with:

• Clear vulnerability descriptions
• Proof of concept evidence
• Risk ratings (CVSS scores)
• Remediation recommendations

Conclusion

This checklist serves as a starting point for web application security testing. Always adapt your methodology based on the specific application and scope of the engagement.