Web Application Methodology

OWASP Testing Guide Approach

Framework Overview

The OWASP Web Security Testing Guide (WSTG) serves as an industry-standard reference for comprehensive vulnerability coverage. Rather than dictating workflow, OWASP provides a checklist to ensure nothing is missed during testing.

OWASP Testing Categories Reference

The OWASP WSTG v4.2 organizes security tests into these categories:

Information Gathering (WSTG-INFO)

Purpose: Collect intelligence about the target application

Key Tests: Search engine reconnaissance, web server fingerprinting, application framework identification, entry point mapping, and architecture analysis.

Output: Comprehensive target profile including technology stack, entry points, and potential attack vectors.

Configuration Management (WSTG-CONF)

Purpose: Identify infrastructure and platform misconfigurations

Key Tests: Network configuration review, file extension handling, admin interface discovery, HTTP method testing, and cloud storage assessment.

Output: Configuration vulnerability list with specific misconfigurations and their security implications.

Identity & Authentication (WSTG-IDNT/ATHN)

Purpose: Test user identity and authentication mechanisms

Key Tests: User enumeration, default credentials, password policies, multi-factor authentication, and account lockout mechanisms.

Output: Authentication bypass opportunities and weakness documentation.

Authorization Testing (WSTG-ATHZ)

Purpose: Verify access control implementation

Key Tests: Directory traversal, privilege escalation, insecure direct object references, and role-based access bypass.

Output: Authorization flaw documentation with impact assessment.

Session Management (WSTG-SESS)

Purpose: Analyze session handling security

Key Tests: Session token analysis, session fixation, cross-site request forgery, and session timeout validation.

Output: Session security assessment with identified weaknesses.

Input Validation (WSTG-INPV)

Purpose: Test data validation and sanitization

Key Tests: Cross-site scripting (XSS), SQL injection, command injection, template injection, and request smuggling.

Output: Input validation vulnerabilities with exploitation proof-of-concepts.

Error Handling (WSTG-ERRH)

Purpose: Assess error message security

Key Tests: Information disclosure through errors, stack trace analysis, and custom error page testing.

Output: Information leakage assessment and disclosure risks.

Cryptography (WSTG-CRYP)

Purpose: Evaluate cryptographic implementations

Key Tests: TLS/SSL configuration, encryption strength analysis, certificate validation, and cryptographic storage.

Output: Cryptographic weakness report with remediation priorities.

Business Logic (WSTG-BUSL)

Purpose: Test application workflow integrity

Key Tests: Data validation logic, process timing attacks, workflow circumvention, and function abuse.

Output: Business logic flaw documentation with business impact analysis.

Client-Side Testing (WSTG-CLNT)

Purpose: Assess client-side security controls

Key Tests: DOM-based XSS, client-side resource manipulation, CORS policy testing, and clickjacking assessment.

Output: Client-side vulnerability report with browser-specific findings.

API Testing (WSTG-APIT)

Purpose: Evaluate API security implementation

Key Tests: GraphQL security testing, REST API vulnerabilities, API authentication bypass, and rate limiting assessment.

Output: API security assessment with integration point vulnerabilities

Key Insight: OWASP provides the what to test, but your workflow determines when and how to test efficiently.

---

Web Application Architecture

Modern Architecture Assessment

Understanding application architecture is crucial for identifying attack vectors and determining effective testing approaches.

Architecture Analysis Framework

Technology Stack Identification

Objective: Map all technologies used in the application

Frontend Technologies include JavaScript frameworks like React, Angular, and Vue.js, along with CSS frameworks, build tools, bundlers, and content delivery networks (CDNs). Understanding the frontend stack helps identify client-side vulnerabilities and attack vectors specific to particular frameworks.

Backend Technologies encompass web servers like Apache, Nginx, and IIS, application frameworks, database systems, and caching mechanisms. Backend analysis reveals server-side vulnerabilities and potential privilege escalation paths.

Tools for Detection include the Wappalyzer browser extension for automated technology identification, WhatWeb command-line tool for comprehensive fingerprinting, Nuclei technology detection templates for systematic scanning, and manual header analysis for detailed information gathering.

Application Topology Mapping

Objective: Understand application structure and data flow

Component Analysis involves identifying entry points and user interfaces, mapping API endpoints and integration points, analyzing database connections, and documenting external service dependencies. This creates a comprehensive view of the application's attack surface.

Architecture Patterns vary significantly and include monolithic applications with single deployments, microservices architecture with distributed components, serverless functions with cloud-based execution, and single-page applications (SPAs) with client-side rendering. Each pattern requires different testing approaches.

Documentation Methods include creating network topology diagrams, mapping data flows between components, identifying trust boundaries, and developing service dependency charts. These visual representations help identify potential attack paths and security boundaries.

Security Control Identification

Objective: Catalog existing security mechanisms

Web Application Firewalls (WAF) require detection and fingerprinting to understand protection mechanisms, rule analysis to identify bypass opportunities, and rate limiting assessment to understand traffic controls. Understanding WAF behavior is crucial for effective testing.

Authentication Systems include single sign-on (SSO) implementations, multi-factor authentication mechanisms, session management approaches, and API authentication methods. Each system type presents unique attack vectors and bypass opportunities.

Security Headers encompass Content Security Policy (CSP), HTTP Strict Transport Security (HSTS), Cross-Origin Resource Sharing (CORS), and other security headers. These headers provide insight into implemented security controls and potential bypass opportunities.

Architecture-Specific Testing Considerations

Different architectures require different testing approaches:

• Single Page Applications (SPAs): Focus on client-side vulnerabilities, API security, and authentication token handling.

• Microservices: Emphasize service-to-service communication, API gateway security, and inter-service authentication.

• Cloud-Native Apps: Consider container security, serverless function vulnerabilities, and cloud storage misconfigurations.

---

Testing Workflow

Practical Testing Workflow Design

Effective workflow design optimizes time, ensures comprehensive coverage, and delivers maximum value to clients.

Time-Boxed Testing Approach

Phase 1: Rapid Assessment (25% of time)

Objective: Quick identification of obvious vulnerabilities

Activities focus on automated vulnerability scanning to establish baseline security posture, basic configuration testing to identify common misconfigurations, common vulnerability checks against known issues, and low-hanging fruit identification for immediate impact.

Expected Outcomes include an initial vulnerability list prioritized by risk, risk priority assessment for resource allocation, testing strategy refinement based on initial findings, and quick wins documentation for immediate client value.

Time Allocation Example in a five-day engagement dedicates the first day to reconnaissance and automated scanning, focusing on immediate actionable findings that provide early value to the client.

Phase 2: Deep Technical Testing (40% of time)

Objective: Comprehensive manual testing and validation

Activities involve manual vulnerability validation to confirm automated findings, complex attack chain development for advanced exploitation, business logic testing for application-specific flaws, and custom payload development for bypass techniques.

Expected Outcomes produce a validated vulnerability list with confirmed exploitability, proof-of-concept exploits demonstrating impact, impact assessment documentation for business understanding, and chain attack scenarios showing advanced compromise paths.

Time Allocation Example uses days two and three for manual testing and exploitation, focusing on high-impact vulnerabilities that require human analysis and creative attack approaches.

Phase 3: Business Logic & Edge Cases (25% of time)

Objective: Test application-specific vulnerabilities

Activities include workflow circumvention testing for business process bypass, race condition analysis for timing-based attacks, advanced authentication bypass techniques, and complex business logic flaw identification.

Expected Outcomes provide business logic vulnerability documentation with application-specific context, advanced attack scenarios beyond common vulnerabilities, application-specific findings unique to the target, and edge case exploitation for comprehensive coverage.

Time Allocation Example dedicates day four to business logic and advanced testing, focusing on unique application vulnerabilities that automated tools cannot identify.

Phase 4: Documentation & Reporting (10% of time)

Objective: Professional documentation and client deliverables

Activities encompass evidence compilation and organization for clear presentation, risk assessment completion with business context, executive summary creation for stakeholder communication, and remediation guidance development for actionable outcomes.

Expected Outcomes deliver a professional penetration testing report with clear findings, executive presentation materials for business stakeholders, technical remediation guidance for development teams, and follow-up testing recommendations for continuous improvement.

Time Allocation Example uses day five for report writing and client presentation, focusing on clear communication of findings and actionable recommendations.

Risk-Based Testing Prioritization

Authentication Bypass

• Direct access to sensitive functionality

• Administrative interface compromise

• Multi-factor authentication bypass

Data Exposure

• SQL injection with data extraction

• Directory traversal accessing sensitive files

• Information disclosure vulnerabilities

Input Validation

• Cross-site scripting (XSS)

• Command injection

• File upload vulnerabilities

Session Management

• Session fixation

• Insecure session handling

• Cross-site request forgery

Configuration Issues

• Information disclosure

• Unnecessary services

• Security header misconfiguration

Business Logic

• Workflow bypass

• Rate limiting bypass

• Function abuse