Web Vulnerability Assessment Methodology

A systematic checklist for comprehensive web application security testing. Use this as your guide when conducting security assessments.

Quick Start Workflow

1. Reconnaissance: Map the application, identify technologies, enumerate endpoints
2. Proxy Analysis: Check for intermediary proxy vulnerabilities
3. Input Testing: Test all user-controllable inputs
4. Authentication/Authorization: Test login, 2FA, session management
5. File Operations: Test upload/download functionality
6. API Testing: Test all API endpoints
7. Framework-Specific: Check for framework-specific vulnerabilities

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1. Proxy & Middleware Vulnerabilities

Modern web applications use proxies that can be exploited. Test these when you identify intermediary infrastructure:

Core Proxy Attacks

• Hop-by-hop headers: Check for header manipulation vulnerabilities
• Cache Poisoning/Deception: Test cache behavior with different inputs
• HTTP Request/Response Smuggling: Test for desync attacks between proxies
• H2C Smuggling: Test HTTP/2 cleartext smuggling
• Server Side Inclusion (SSI/ESI): Test for template injection via edge servers
• Cloudflare bypass: Attempt to bypass WAF protections
• XSLT Injection: Test for stylesheet injection
• WAF bypass: Test for filter evasion techniques

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2. User Input Vectors

Reflected Input Testing

When user data appears in responses, test for:

• XSS: Cross-site scripting (stored, reflected, DOM-based)
• Command Injection: OS command execution
• SSRF: Server-side request forgery
• SSTI: Server-side template injection
• Path Traversal: File system access (

  ../

  sequences)
• Open Redirect: URL manipulation attacks
• CRLF Injection: HTTP header injection
• Prototype Pollution: JavaScript object manipulation
• XSSI: Cross-site script inclusion
• Client-Side Template Injection: Template engine exploitation
• Dangling Markup: HTML/scriptless injection
• Reverse Tab Nabbing: Window manipulation attacks

Search Functionality

Test search features for:

• SQL Injection: Database manipulation
• NoSQL Injection: Document database attacks
• LDAP Injection: Directory service attacks
• XPath Injection: XML query manipulation
• ReDoS: Regular expression denial of service
• ORM Injection: Object-relational mapping attacks
• RSQL Injection: REST query parameter attacks

Forms & WebSockets

Test form submissions and WebSocket connections for:

• CSRF: Cross-site request forgery
• CSWSH: Cross-site WebSocket hijacking
• PostMessage: Cross-origin messaging vulnerabilities
• Phone Number Injection: SMS/voice injection attacks

HTTP Headers

Check for header-related vulnerabilities:

• Clickjacking: UI redressing attacks
• CSP Bypass: Content Security Policy evasion
• CORS Misconfiguration: Cross-origin resource sharing issues
• Cookie Manipulation: Session hijacking
• Iframe Traps: Click isolation attacks

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3. Authentication & Authorization

Bypass Techniques

Test authentication mechanisms for:

• 2FA/OTP Bypass: Multi-factor authentication evasion
• Login Bypass: Authentication circumvention
• Password Reset Bypass: Account recovery manipulation
• Account Takeover: Credential compromise
• Race Conditions: Timing-based attacks
• Rate Limit Bypass: Request throttling evasion
• Captcha Bypass: Automated challenge completion
• Payment Bypass: Transaction manipulation
• Registration Vulnerabilities: Account creation abuse

Authorization Issues

• IDOR: Insecure direct object references
• Mass Assignment: Property injection attacks
• Parameter Pollution: Query parameter manipulation
• Unicode Normalization: Character encoding attacks

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4. Data Format Vulnerabilities

Structured Data

Test for format-specific attacks:

• Deserialization: Object deserialization attacks
• JWT Vulnerabilities: Token manipulation and forgery
• XXE: XML external entity injection
• JSON/XML/YAML Hacking: Data format attacks
• GraphQL Attacks: API query manipulation
• gRPC-Web: Protocol-specific vulnerabilities
• SOAP/JAX-WS: Web service attacks

File Operations

Test file handling for:

• File Upload: Malicious file execution
• Formula Injection: Spreadsheet formula attacks (CSV, DOC, LaTeX)
• PDF Injection: Document manipulation
• Server-Side XSS: Dynamic content injection in generated files

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5. Identity & Integration

External Identity

• OAuth to Account Takeover: Authorization flow attacks
• SAML Attacks: Security assertion manipulation

Third-Party Integrations

• Domain/Subdomain Takeover: DNS hijacking
• Storage Buckets: Cloud storage misconfiguration (S3, Firebase)
• Artifactory: Package registry attacks
• Code Review Tools: CI/CD pipeline attacks
• Imagemagick Security: Image processing vulnerabilities

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6. Infrastructure & Frameworks

Web Servers

• Apache: Server-specific vulnerabilities
• Nginx: Reverse proxy attacks
• IIS: Windows server attacks
• Tomcat: Java application server attacks
• Spring Actuators: Management endpoint exposure
• WebDAV: File protocol attacks (PUT method)
• WSGI: Python deployment attacks
• Werkzeug: Debug endpoint exposure
• Special HTTP Headers: Header-based attacks

Application Frameworks

• Django: Python framework attacks
• Flask: Micro-framework vulnerabilities
• NodeJS/Express: JavaScript runtime attacks
• Angular: Frontend framework attacks
• Vue/Nuxt: Modern frontend attacks
• Next.js: React framework attacks
• Laravel: PHP framework attacks
• Symfony: PHP framework attacks

CMS & Platforms

• WordPress: Plugin/theme vulnerabilities
• Joomla: CMS-specific attacks
• Drupal: Enterprise CMS attacks
• Moodle: LMS vulnerabilities
• Prestashop: E-commerce attacks
• Jira: Project management attacks
• Grafana: Monitoring dashboard attacks
• Rocket.Chat: Communication platform attacks
• Zabbix: Monitoring system attacks
• SharePoint: Enterprise collaboration attacks
• Sitecore: CMS platform attacks

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7. Supply Chain & Modern Vectors

Build Pipeline Attacks

• Dependency Confusion: Package registry poisoning
• Timing Attacks: Side-channel information leakage
• UUID Insecurities: Predictable identifier attacks

Emerging Technologies

• dApps: Decentralized application attacks
• Browser Extensions: Add-on vulnerabilities
• Web Fuzzing: Automated vulnerability discovery with wfuzz

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Testing Workflow

Phase 1: Reconnaissance

1. Map all endpoints and parameters
2. Identify technologies (Wappalyzer, manual inspection)
3. Document authentication flows
4. Enumerate subdomains and related assets

Phase 2: Systematic Testing

1. Work through each category in this checklist
2. Test all user-controllable inputs
3. Check for reflected, stored, and processed data
4. Test authentication and authorization boundaries

Phase 3: Documentation

1. Record all vulnerabilities with evidence
2. Include reproduction steps
3. Note affected endpoints and parameters
4. Assess severity and impact

Phase 4: Prioritization

1. Rank by severity (CVSS scoring)
2. Consider exploitability
3. Evaluate business impact
4. Identify chainable vulnerabilities

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Key Principles

• Think like an attacker: Consider all possible attack vectors, not just the obvious ones
• Test edge cases: Boundary conditions often reveal vulnerabilities
• Chain vulnerabilities: Combine multiple issues for greater impact
• Stay updated: New vulnerabilities emerge regularly; check CVE databases
• Document everything: Clear documentation aids remediation and future testing
• Respect scope: Only test authorized targets
• Be thorough: Hidden endpoints and parameters often contain the most critical bugs

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When to Use This Skill

Use this methodology when:

• Conducting a web application security assessment
• Performing bug bounty hunting
• Reviewing code for security issues
• Designing secure applications
• Creating security test plans
• Training security teams
• Auditing third-party applications
• Preparing for penetration testing engagements

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References

• OWASP Testing Guide
• OWASP Top 10
• PortSwigger Web Security Academy
• HackTricks Web Pentesting
• NIST Security Guidelines