Penetration testing of web applications

A web application penetration test is a targeted attack simulation focused on your web applications, portals, and interfaces accessible from both the internet and internal networks. Today, web applications are the most common entry point for attackers.

Non-binding consultation

Web Application Penetration Testing

They process sensitive data, authenticate users, and connect internal systems with the outside world. We test the security of application logic, authentication, authorization, session management, input validation, and protection against the most widespread vulnerabilities according to the OWASP methodology. The output is a detailed report featuring discovered vulnerabilities, proof of their exploitability, and specific recommendations for both the development team and application administrators.

A web application penetration test examines the security of the entire application from an attacker’s perspective, from the login page to the deepest functionalities available to authorized users.

We focus on vulnerabilities such as SQL Injection, Cross-Site Scripting (XSS), Server-Side Request Forgery (SSRF), authentication and authorization flaws, insecure deserialization, sensitive data exposure, and other vulnerabilities from the current OWASP Top 10.

We test the application from the perspective of both an unauthenticated attacker and a logged-in user with various permission levels to uncover access control flaws between individual roles. The result will show whether your application can withstand a real attack and where improvements are needed.

Are you more interested in infrastructure testing? Go to the Infrastructure Penetration Testing page, or view the penetration testing overview.

API Penetration Testing

An API penetration test focuses on the security of your application programming interfaces: REST, GraphQL, SOAP, and other types. APIs form the backbone of modern applications and often expose sensitive data and critical functions without the traditional user layer serving as a protective barrier.

We test the authentication and authorization of individual endpoints, token and API key management, input data validation, protection against Broken Object Level Authorization (BOLA/IDOR), rate limiting, and correct API behavior during unexpected requests.

We verify whether the API provides more data than necessary, whether access permissions can be bypassed, and whether sensitive operations are sufficiently protected. The test is based on the OWASP API Security Top 10 methodology and reveals vulnerabilities that a classic web application test might not cover.

What You Get

Manual and Automated Testing

We combine automated scanners with manual testing to uncover vulnerabilities that tools alone cannot find.

Detailed Report with PoC

Each finding includes a description, CVSS rating, proof-of-concept, and specific remediation steps clear to developers.

Retesting After Remediation

After the implementation of fixes, we perform a re-verification of the discovered vulnerabilities to confirm the effectiveness of the corrective measures.

Methodology

We test according to recognized standards such as the OWASP Testing Guide, OWASP ASVS, and PTES. We cover both the complete OWASP methodology and specifically the OWASP Top 10 – depending on the needs and scope of the project.

Every test combines automated scanning with thorough manual verification to ensure nothing is overlooked. The output is a clear report with findings classified by severity and a clear remediation plan.

Why SysnetShield?

There are many companies on the market offering security services. Here is the specific difference–and the people behind it:

Patrik Žák

Ethical Hacker and Red Teamer focusing on infrastructure

Patrik Žák’s Profile →

Juraj Daniš

Ethical Hacker focusing on web applications

Juraj Daniš’s Profile →

Team Certifications

Both CRTO and CPTS are fully practical certifications–the exam consists of a multi-day attack in a laboratory environment and the preparation of a report, not a multiple-choice test.

What sets us apart

Specialized team, not subcontractors

We are not a consultancy firm that resells work. Every project is led directly by members of our team with full responsibility for the result.

Manual work, not just automated tools

Automated scanners detect known vulnerabilities. Logic errors, business-logic flaws, and exploit chains can only be uncovered by an experienced tester who thinks like an attacker.

Actionable outputs

The report is not an academic exercise. It is written so that your dev or ops team can start remediation immediately–with specific steps and links to resources.

Tailored scenarios, not templates

We build every project according to your environment, your risks, and your goals. We do not use off-the-shelf methodologies or generic templates.

Discretion and confidentiality

We sign an NDA before every project. All information and results remain exclusively between us and you.

Compliance with international standards

The methodology is based on OWASP, PTES, and NIST and is in compliance with NIS2 and the Cybersecurity Act–meaning it is recognized by regulators and auditors.

Find Out the State of Your Security

Leave us your contact details and we will get back to you within 24 hours for a non-binding consultation. We will discuss the scope, approach, and price. We respond within 24 hours · non-binding initial consultation · tailored price offer.