OSCP Certification: Exploiting the OWASP Top 10 Vulnerabilities for Penetration Testing

Web application security is relevant to the practical penetration-testing skills developed through OffSec PEN-200, but the OWASP Top 10 is an awareness and prioritization resource, not the complete OSCP examination syllabus. The current OWASP Top 10 is the 2025 edition, and its category names differ from those used in 2021. Candidates should use the official OffSec exam guide for the assessed tasks and the OWASP publication for modern application-risk context.

All testing described here belongs in an intentionally vulnerable application, isolated laboratory, or environment where the tester has explicit permission. Ethical testing means agreeing on scope, collecting the minimum evidence needed, avoiding unnecessary access to real data, and documenting how a weakness should be fixed.

A01:2025 Broken Access Control

Authorization failures arise when users can reach resources or operations beyond their assigned permissions. In a lab, compare the behavior of multiple test identities to establish whether the server enforces ownership and role boundaries rather than trusting parameters or interface controls.

For exam preparation, explain the expected permission, the observed deviation, the affected asset and the remediation: server-side authorization checks on every sensitive request. Do not equate a guessed resource identifier with proven unauthorized access.

A02:2025 Security Misconfiguration

Default settings, unnecessary services, verbose error messages, exposed administrative functions and inconsistent deployment configuration can increase an application’s attack surface. The impact depends on what the setting exposes and whether other controls limit access.

Build a review checklist covering debug modes, access permissions, configuration drift, exposed components and secure defaults. Test changes on owned systems, then verify that the intended protection survives deployment.

A03:2025 Software Supply Chain Failures

Applications depend on packages, build tools, container images and delivery pipelines. Risks include compromised dependencies, vulnerable components and untrusted build artifacts. Merely identifying an outdated library does not establish an exploitable path.

A responsible assessment considers asset inventory, version provenance, dependency reachability, signing, build permissions and patching evidence. Defenders should maintain an inventory and verify the integrity of software delivered to production.

A04:2025 Cryptographic Failures

Encryption protects data in transit and at rest only when the algorithms, keys, protocols and configurations are appropriate. Strong cryptography cannot compensate for access-control failures or exposure of encryption keys.

Review whether sensitive information is transmitted securely, whether certificates are validated and whether secrets are stored in protected systems. Avoid handling real users’ credentials or keys outside permitted scope.

A05:2025 Injection

Injection occurs when untrusted input is interpreted as commands or queries by a downstream component. The same underlying boundary problem can affect database statements, system calls and other interpreters.

In a permitted training application, distinguish data from executable instructions. Study parameterized queries, contextual output encoding, input validation and least-privilege service accounts as complementary mitigations.

A06:2025 Insecure Design

Insecure design describes weaknesses rooted in requirements or architecture rather than an isolated coding mistake. A workflow that permits high-value actions without identity checks cannot be fixed simply by hiding a button.

Apply threat modeling to a sample application: identify assets, trust boundaries, abuse cases, authentication dependencies and recovery needs. Document which design control prevents each meaningful failure mode.

A07:2025 Authentication Failures

Authentication weaknesses can permit account compromise through poor credential handling, session management or verification workflows. Authentication and authorization solve different problems: knowing who a user is does not prove they may access every resource.

Practice evaluating password reset design, multi-factor enrollment, session lifetime and account recovery using disposable test identities. Robust systems provide appropriate rate limits, secure session rotation and verified recovery paths.

A08:2025 Software or Data Integrity Failures

Integrity failures can arise when an application trusts code, configuration or data that should be authenticated. The risk can affect update systems, continuous delivery and the handling of serialized or externally supplied content.

Defensive controls include signed artifacts, protected branches, reviewable deployment pipelines and strict validation at trust boundaries. A finding should identify how the untrusted input reaches a consequential decision.

A09:2025 Security Logging and Alerting Failures

A security control may exist yet remain ineffective if abuse is neither recorded nor surfaced to the correct team. Logs should enable investigation without collecting sensitive information indiscriminately.

Test whether significant authentication, administrative and access-control events produce useful evidence. Validate alert routing, time synchronization, retention, redaction and the responder’s ability to reconstruct an event.

A10:2025 Mishandling of Exceptional Conditions

Unexpected failures, resource limits and unusual application states can become security risks when error handling exposes information or leaves operations incomplete. Safe handling includes consistent transaction behavior, controlled failure messages and recovery.

Use bounded negative tests in a sandbox to observe how the application behaves when inputs, dependencies or services fail. Document whether the outcome is safe, explainable and recoverable.

Connect OWASP understanding to PEN-200 skills

The OffSec PEN-200 and OSCP+ pathway encompasses network enumeration, privilege boundaries, Active Directory, practical analysis and documentation alongside web vulnerabilities. The OWASP list is therefore a useful application-security complement, not a promise that ten categories map one-to-one to exam points.

A useful study report states the tested condition, scope, relevant output, business impact, remediation and verification. The goal is a defensible technical assessment rather than a collection of attack strings memorized without context.

Conclusion: Test responsibly and document what matters

Use OWASP Top 10:2025 to organize common application risks and OffSec’s current documentation to determine exam expectations. In authorized labs, connect each risk to observable behavior and a protective design choice. Good penetration testing ends with evidence and useful remediation.