Penetration Testing Explained
OWASP Top 10 Penetration Testing Checklist (2026)
The OWASP Top 10 penetration testing checklist covers testing for broken access control, cryptographic failures, injection attacks, insecure design, security misconfiguration, vulnerable components, authentication failures, data integrity failures, logging gaps, and server-side request forgery.
Andreas Johansson · Chief Executive Officer
Senior IT management leader with 25 years of experience in Cloud, Security, and Datacenter infrastructure.
Why the OWASP Top 10 Matters for Pentesting
The OWASP Top 10 is the globally recognized standard for web application security risks. It provides a prioritized list of the most critical vulnerabilities that testers should evaluate in every web application penetration test. Regulatory frameworks including PCI DSS, SOC 2, and ISO 27001 reference OWASP as a baseline for application security testing.
Using the OWASP Top 10 as a checklist ensures consistent, comprehensive coverage across pentesting engagements.
A01: Broken Access Control
- What to test: Can users access resources or perform actions beyond their intended permissions?
Access control testing includes:
- Accessing other users' data by manipulating IDs or parameters
- Bypassing role-based restrictions to reach admin functionality
- Exploiting CORS misconfigurations
- Manipulating JWTs or session tokens to escalate privileges
- Accessing API endpoints without proper authorization checks
This is the #1 risk because access control failures directly lead to unauthorized data access and system compromise.
A02: Cryptographic Failures
- What to test: Is sensitive data properly protected in transit and at rest?
- TLS configuration — version, cipher suites, certificate validity
- Password hashing — algorithms (bcrypt, argon2 vs MD5, SHA1)
- Encryption of sensitive database fields
- Key management practices
- Exposure of sensitive data in URLs, logs, or error messages
A03: Injection
- What to test: Can malicious input alter the intended behavior of queries or commands?
- SQL injection across all input parameters
- Cross-site scripting (XSS) — stored, reflected, and DOM-based
- Command injection through file uploads or system calls
- LDAP, XML, and template injection
- NoSQL injection in MongoDB or similar databases
A04: Insecure Design
- What to test: Are there fundamental design flaws that no amount of implementation fixing can address?
- Business logic bypass (e.g., skipping payment steps, manipulating workflows)
- Missing rate limiting on sensitive operations
- Insufficient anti-automation controls
- Trust boundary violations
- Lack of defense-in-depth patterns
A05: Security Misconfiguration
- What to test: Are default configurations, unnecessary features, or improper settings creating vulnerabilities?
- Default credentials on admin panels, databases, and services
- Unnecessary HTTP methods enabled
- Directory listing enabled
- Verbose error messages exposing stack traces
- Missing security headers (CSP, HSTS, X-Frame-Options)
- Cloud service misconfigurations (open S3 buckets, permissive security groups)
A06: Vulnerable and Outdated Components
- What to test: Are third-party libraries, frameworks, or dependencies introducing known vulnerabilities?
- Software composition analysis for known CVEs
- Outdated JavaScript libraries (frontend and backend)
- Unpatched server software and operating systems
- End-of-life software no longer receiving security updates
A07: Identification and Authentication Failures
- What to test: Can authentication mechanisms be bypassed, brute-forced, or manipulated?
- Credential stuffing and brute force resistance
- Password policy enforcement
- Multi-factor authentication bypass
- Session fixation and session management
- Account enumeration through login/registration responses
A08: Software and Data Integrity Failures
- What to test: Can the integrity of software updates, CI/CD pipelines, or data be compromised?
- Insecure deserialization vulnerabilities
- CI/CD pipeline security — unsigned deployments, compromised dependencies
- Integrity verification of software updates
- Client-side data manipulation (hidden fields, cookies, local storage)
A09: Security Logging and Monitoring Failures
- What to test: Would an attacker's activities be detected and investigated?
- Logging of authentication events (successes and failures)
- Detection of injection attempts and access control violations
- Alert mechanisms for suspicious activity
- Log integrity — can attackers tamper with logs?
- Incident response integration
A10: Server-Side Request Forgery (SSRF)
- What to test: Can the application be tricked into making requests to unintended destinations?
- URL input parameters that fetch remote resources
- Internal service access through SSRF (metadata endpoints, internal APIs)
- Cloud metadata service access (169.254.169.254)
- DNS rebinding attacks
- File protocol handler abuse
Applying This Checklist
Use this checklist as a minimum baseline for web application pentesting. Experienced testers will go beyond the OWASP Top 10 to test application-specific business logic, race conditions, and complex attack chains.
How SeqOps fits
SeqOps doesn't do penetration testing; it complements it. Between engagements it keeps checking your cloud configuration and servers for known vulnerabilities and misconfigurations, so each pentest can focus on what automated scanning can't find.