Web Application Penetration Testing

We test the security of web applications by simulating real-world attacks. Our ethical hackers verify the exploitability of vulnerabilities according to the OWASP Web Security Testing Guide and OWASP Top 10 and provide clear recommendations to improve your security posture.

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Why Test Web Applications?

Web applications are among the most common targets of cyberattacks because they are accessible from the internet and often process sensitive user and organizational data. A single flaw in authentication, authorization, input validation, or configuration can allow an attacker to gain unauthorized access, steal data, disrupt operations, or compromise other systems within the organization. Penetration testing simulates real-world attack scenarios and verifies whether identified vulnerabilities can actually be exploited. Our ethical hackers combine automated tools with manual testing based on the OWASP Web Security Testing Guide and OWASP Top 10. The result is not just a list of findings, but verified vulnerabilities supported by evidence of exploitability and specific recommendations for remediation. Regular penetration testing helps organizations reduce security risks, protect sensitive data, and support compliance with standards and regulations such as NIS2, DORA, ISO 27001, and PCI DSS. It also helps uncover complex attack scenarios and business logic flaws that automated security scanners may fail to detect.

Protection of Sensitive Data

We identify vulnerabilities that could lead to the exposure of personal data, login credentials, business information, or other sensitive data processed by the web application.

Prevention of Financial and Operational Damage

A successful attack can cause service outages, data loss, financial damage, and reputational harm. Penetration testing helps identify risks before attackers can exploit them.

Support for Compliance with Security Standards

Penetration testing results can support compliance with the requirements of NIS2, DORA, ISO 27001, and PCI DSS, which require regular security assessments of information systems.

Greater Trust from Customers and Partners

A secure web application reduces the risk of security incidents and strengthens the confidence of customers, business partners, and investors in the reliability of your digital services.

What We Test

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Authentication and Authorization

We test login mechanisms, user account management, password resets, and the correct configuration of access permissions.

Input Validation

We test how user input is processed and assess the application's resilience against SQL Injection, Cross-Site Scripting (XSS), Command Injection, and other attacks.

Session Management

We assess the security of session cookies, timeouts, tokens, and protection against session hijacking.

Business Logic

We verify whether the application can be abused in ways that its developers did not anticipate.

APIs

We test REST and GraphQL APIs, including authentication, authorization, and protection against abuse.

File Uploads

We assess the security of file upload functionality and whether it can be exploited to execute malicious code.

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What Can Web Application Penetration Testing Reveal?

Penetration testing does not only uncover individual technical flaws. It also verifies how multiple vulnerabilities can be combined and what real-world impact they may have on the security of the application, its users, and the entire organization. Our ethical hackers therefore test not only known vulnerability types, but also the application's business logic, access controls, and potential abuse scenarios. Typical findings include:

Authorization and access control flaws can allow attackers to view, modify, or delete other users' data or gain access to information they should not be authorized to access.

Weaknesses in authentication, session management, or password reset processes can lead to authentication bypass and the takeover of user accounts.

Vulnerabilities such as SQL Injection or Command Injection can allow attackers to manipulate databases, execute commands, or gain control over parts of the server infrastructure.

Cross-Site Scripting (XSS) can allow malicious code to be executed in a user's browser, potentially resulting in the theft of sensitive information or abuse of an active session.

Business logic flaws can allow attackers to use legitimate application functionality in unintended ways and bypass security or process restrictions.

Insufficiently secured file upload functionality can allow attackers to upload malicious content, bypass security controls, or, in severe cases, execute code on the server.

Certain web application vulnerabilities can allow attackers to communicate with internal services and systems that are not directly accessible from the internet.

Application or configuration flaws can lead to the exposure of personal data, login credentials, tokens, internal information, or other sensitive data.

Free Report

Discover What Hundreds of Real-World Penetration Tests Reveal

Web applications are among the most frequently tested digital environments. Download our free Ethical Hacking Report 2025 and discover what we found across 628 penetration tests and an analysis of 3,293 identified vulnerabilities in Citadelo projects.

The most common vulnerabilities found in real-world security projects
How vulnerabilities have evolved compared to 2024
Analysis of web applications, APIs, cloud environments, infrastructure, and AI
Practical recommendations from experienced ethical hackers

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Choose Your Penetration Testing Type

Penetration Testing

Penetration testing (pentesting) simulates real-world cyberattacks to identify vulnerabilities before attackers can exploit them. Learn how penetration testing works, what types of pentests we perform, what you receive after the test, and how we help you reduce cybersecurity risks.

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Mobile Applications

Mobile application penetration testing for Android and iOS assesses the security of sensitive data, APIs, server communication, local storage, and the application's resilience against reverse engineering, rooting, jailbreaking, and other attack techniques.

Learn about mobile apps

AI and LLM Systems

We test the security of AI applications, chatbots, AI agents, and RAG systems. AI penetration testing assesses resilience against prompt injection, jailbreak attacks, sensitive data leakage, model manipulation, and abuse of external tools based on the OWASP Top 10 for LLM Applications.

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Network Infrastructure and Internal Systems

We simulate attacks against internal and external infrastructure, including firewalls, VPNs, Active Directory, servers, and databases. Network infrastructure penetration testing assesses network configuration, segmentation, privilege escalation, and an attacker's ability to move laterally across systems.

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Cloud Environments

We assess the security of AWS, Microsoft Azure, and Google Cloud Platform (GCP) environments by simulating real-world attacks. Cloud penetration testing covers IAM, cloud storage, Kubernetes, network rules, and exposed services.

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APIs and Microservices

API and microservices penetration testing assesses the security of REST, GraphQL, and other APIs, including communication between microservices. We test OAuth, JWT, API gateways, authorization, input validation, and API resilience based on the OWASP API Security Top 10.

Learn about APIs