Performing Web Application Penetration Test

When to Use

• Testing web applications before production deployment to identify exploitable vulnerabilities
• Conducting compliance-driven security assessments (PCI-DSS requirement 6.6, SOC 2 Type II)
• Validating remediation of previously identified web application vulnerabilities during retesting
• Assessing third-party web applications before integration into the organization's environment
• Evaluating custom-developed web applications where automated scanning alone is insufficient

Do not use against web applications without written authorization, against production systems during peak traffic hours without explicit approval, or for denial-of-service testing of web infrastructure.

Prerequisites

• Signed statement of work (SoW) defining the target application URLs, environments (staging/production), and testing boundaries
• Burp Suite Professional license with up-to-date extensions (Active Scan++, Autorize, JSON Beautifier, Logger++)
• Valid test accounts at each privilege level (unauthenticated, standard user, administrator) for authorization testing
• Application documentation including API specifications (OpenAPI/Swagger), sitemap, and technology stack details
• Browser configured with Burp Suite proxy (FoxyProxy recommended) and Burp CA certificate installed

Workflow

Step 1: Reconnaissance and Application Mapping

Map the entire attack surface of the web application:

• Configure Burp Suite proxy and spider the application by browsing every page, form, and function manually while Burp captures the sitemap
• Use Burp's Discover Content feature to find hidden directories and files not linked from the visible application
• Identify the technology stack from response headers (X-Powered-By, Server), cookies (JSESSIONID = Java, PHPSESSID = PHP, ASP.NET_SessionId = .NET), and page extensions
• Enumerate endpoints using ffuf -w /usr/share/seclists/Discovery/Web-Content/directory-list-2.3-medium.txt -u https://target.com/FUZZ -mc 200,301,302,403
• Review JavaScript files for hardcoded API endpoints, secrets, and client-side routing using Burp's JS Link Finder extension or LinkFinder.py
• Document all entry points: URL parameters, POST bodies, HTTP headers, cookies, file uploads, and WebSocket connections

Step 2: Authentication Testing

Test authentication mechanisms for weaknesses:

• Credential enumeration: Submit valid and invalid usernames to identify differences in response (timing, message, HTTP status) that reveal valid accounts
• Brute force protection: Attempt 10-20 rapid login attempts with invalid credentials to verify account lockout and rate limiting are enforced
• Password policy: Test password creation with weak passwords (123456, password, single character) to verify policy enforcement
• Multi-factor authentication bypass: Test for MFA bypass by directly accessing post-authentication pages, manipulating MFA tokens, or replaying successful MFA responses
• Session fixation: Note the session token before and after authentication. If the token does not change after login, session fixation is possible
• Remember me functionality: Inspect persistent authentication tokens for predictability, encryption, and proper expiration
• Password reset: Test the password reset flow for token predictability, token expiration, account enumeration via the reset form, and host header injection

Step 3: Authorization Testing

Verify that access controls are properly enforced:

• Horizontal privilege escalation (IDOR): Using Account A, capture requests that access Account A's resources. Replay those requests substituting Account B's identifiers (user IDs, order numbers, filenames). Use Burp's Autorize extension to automate this across all endpoints.
• Vertical privilege escalation: Using a low-privilege account, attempt to access administrative functions by directly browsing to admin URLs, modifying role parameters in requests, or manipulating JWT claims
• Forced browsing: Attempt to access resources that should require authentication by directly navigating to internal URLs collected during mapping
• HTTP method tampering: If GET is blocked on an endpoint, try PUT, POST, DELETE, PATCH, or use method override headers (X-HTTP-Method-Override: DELETE)
• Path traversal in authorization: Test URL path manipulation (/api/users/123/../456/profile) to bypass path-based authorization checks

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