Penetration testing
Penetration testing
A penetration test simulates a real-world cyberattack to identify security vulnerabilities before attackers can exploit them. Our certified ethical hackers test web applications, APIs, mobile applications, cloud environments, AI systems, and network infrastructure under realistic attack conditions.
Using the same techniques as real-world attackers, we uncover security risks and provide clear, actionable recommendations to help you remediate them.
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What is penetration testing
Penetration testing is a controlled simulation of a real cyber attack. Our team of highly skilled ethical hackers will test your cyber security. They behave like real attackers in your systems and search for vulnerabilities in your infrastructure, web and mobile applications, or even the cloud. Penetration tests are usually performed manually by our experts using tools and techniques used by real attackers. To enhance efficiency and broaden test coverage, we use our own AI-powered tools during the reconnaissance and analysis phases. However, the final assessment and validation are always performed by an experienced ethical hacker.
This process provides you with key information about security gaps and helps you prepare for real attacks and minimise risks. Penetration tests enable organisations to strengthen their cyber defences and protect their data, customers and reputation.
However, our goal is not to cause damage, but to uncover risks and weaknesses that could be exploited by a real attacker. Penetration tests not only identify vulnerabilities in a company's IT, but also demonstrate how they could be exploited in practice. They include attempts to gain access to company systems, escalate privileges, or exfiltrate data.
A real hacker attack can lead to data loss, disruption of operations, leakage of confidential information or damage to reputation.
Investing in regular penetration testing is a key step in ensuring the security and trustworthiness of your organisation.
Types of Penetration Testing by Access Level
Not every penetration test is performed the same way. The amount of information available to an ethical hacker before testing begins has a significant impact on the testing methodology, attack scenarios, and the overall scope of the security assessment. Choosing the right type of penetration test depends on your objectives, the required level of coverage, and the complexity of your environment. Our experts will help you select the most appropriate approach for your infrastructure, applications, and security requirements. The results also provide valuable input for cyber risk management and support compliance with regulations and standards such as NIS2, DORA, PCI DSS, and ISO/IEC 27001.
Black Box Testing
The ethical hacker has no prior knowledge of the target system. This approach simulates an external attacker attempting to identify and exploit publicly accessible vulnerabilities.
Gray Box Testing
The tester is provided with limited information or standard user access. This approach simulates attacks by a regular user, business partner, or an attacker with partial access to the environment.
White Box Testing
The tester has access to detailed information such as system architecture, source code, configurations, or user permissions. White Box Penetration Testing provides the most comprehensive security assessment and uncovers vulnerabilities that may remain undetected during an external test.
What You Gain from a Penetration Test
Identify Vulnerabilities and Assess Risks
A penetration test provides a detailed assessment of vulnerabilities across your applications, infrastructure, and cloud environments. You gain a clear understanding of which weaknesses attackers could exploit and the level of risk they pose to your organization.
Strengthen the Security of Data and Systems
Every finding includes practical remediation recommendations. This enables you to improve your cybersecurity posture, reduce the risk of security incidents, and better protect sensitive data, business systems, and customer information.
Support Risk Management and Compliance
Penetration testing provides valuable input for cyber risk management and helps meet the requirements of regulations and standards such as NIS2, DORA, ISO/IEC 27001, PCI DSS, and GDPR. Each report includes both technical findings and a management summary.
Understand How Attackers Exploit Weaknesses
We deliver more than a list of vulnerabilities. Our experts demonstrate how attackers could exploit each weakness, explain its potential business impact, and provide clear recommendations to reduce the associated security risks.
Why Choose Citadelo?
Explore the Ethical Hacking Report
Penetration testing has been our core expertise for more than 14 years. Our team of 47 certified security experts holds internationally recognized certifications, including OSCP, OSEP, OSWE, CRTO, PNPT, CISSP, and many others. Every year, we perform more than 600 penetration tests for organizations of all sizes. In 2025 alone, we identified 3,293+ vulnerabilities and discovered 20+ new CVEs, actively contributing to the global cybersecurity community.
We work with Fortune 500 companies as well as organizations in banking, finance, automotive, telecommunications, media, the public sector, crypto, energy, and many other industries. We test web applications, APIs, mobile applications, cloud environments, internal infrastructure, and AI systems using internationally recognized methodologies. Every finding is manually verified by experienced ethical hackers.
Our recommendations are based on real-world penetration testing experience, not theory. Every year, we analyze the results of hundreds of security assessments and publish our findings in the Ethical Hacking Report, providing practical insights into the latest vulnerabilities, attack trends, and cybersecurity risks.
Our Certifications
How does pen testing work?
01
Test planning
Together, we define the objectives, scope, and methodology of the penetration test. We identify the systems to be tested, establish the rules of engagement, and prepare attack scenarios that accurately simulate real-world threats.
02
Information gathering
We collect information about the target environment, applications, infrastructure, and exposed services. This phase helps identify potential attack vectors and prepares realistic penetration testing scenarios.
03
Vulnerability scanning and analysis
Using automated tools and manual analysis, we identify security weaknesses and review system configurations. We verify known vulnerabilities and prepare them for practical validation.
04
Attack Simulation
Our ethical hackers safely exploit identified vulnerabilities using the same techniques as real-world attackers. This validates their actual impact and uncovers risks that automated scanners often miss.
05
Final report
You receive a detailed report describing the identified vulnerabilities, their risk levels, and practical remediation recommendations. It also includes an executive summary to support cyber risk management and compliance with NIS2 and DORA.
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What do we test?
Web applications
We test web applications for vulnerabilities such as SQL Injection, Cross Site Scripting (XSS), authentication flaws, privilege escalation, and other risks covered by the OWASP Top 10.
Mobile Applications
We assess the security of Android and iOS applications by testing data protection, server communication, local storage, authentication, reverse engineering, and resistance to application tampering.
AI & LLM Systems
We assess the security of AI applications, chatbots, AI agents, and RAG systems. We test for prompt injection, jailbreaks, sensitive data leakage, model manipulation, and abuse of external tools and connectors.
Network Infrastructure
We evaluate the security of internal and external networks, including firewalls, routers, VPNs, network services, and other infrastructure components. We identify misconfigurations, vulnerabilities, and unauthorized access paths.
Cloud Solutions
We assess AWS, Microsoft Azure, and Google Cloud environments by reviewing identities, permissions, storage, network configurations, and exposed services for security weaknesses.
APIs and Microservices
We test REST, GraphQL, and other APIs for authentication, authorization, input validation, business logic flaws, and secure communication between services.
Internal Systems & Databases
We evaluate internal systems against insider threats by testing user permissions, network segmentation, database security, Active Directory, and opportunities for lateral movement.
AI Accelerates Testing. Humans Make the Decisions.
See How We Use AI in Penetration Testing
We use artificial intelligence to accelerate analysis, generate test scenarios, and correlate large volumes of security data. Every finding is manually verified by an experienced ethical hacker.
This allows us to cover a broader testing scope, identify more vulnerabilities, and maintain the high quality and accuracy of every penetration test.
How much does penetration testing cost?
Book a Free Consultation
The cost of a penetration test depends on the project scope, the complexity of your environment, and the chosen testing approach. Basic web application penetration tests start at approximately €800, while comprehensive manual assessments of infrastructure, cloud environments, or Red Teaming engagements can cost €10,000 or more.
We will provide a tailored quote after an initial consultation and an assessment of your requirements.
Experienced Ethical Hackers Behind Every Penetration Test
Our experience comes from hundreds of penetration tests covering web applications, mobile applications, cloud environments, APIs, and AI systems. As a result, we uncover vulnerabilities that automated scanners often fail to detect.
Book a Free ConsultationWhat else do you ask us
Questions we hear most often about penetration testing
Because attackers are already trying. A penetration test shows you which weaknesses in your IT systems hackers could exploit. It gives you a clear list of vulnerabilities, the specific business impact they could cause, and most importantly, a concrete roadmap for fixing them.
It depends on the scope. A simple web application test can be completed in a few days. A full-scale infrastructure assessment may take several weeks. At the very beginning, we provide you with a clear schedule—and we stick to it.
Best practice is at least once a year. In addition, you should repeat the test whenever you deploy a new critical application or make major changes to your IT infrastructure. Regular testing is the only way to be sure new changes haven’t introduced new vulnerabilities.
The report is a practical guide, not shelfware. It includes identified vulnerabilities ranked by risk, descriptions of their impact and possible exploitation paths, as well as our concrete remediation recommendations. There’s also an executive summary in language your management will understand. The exact structure of the report depends on what and how we test. Once we know more about your environment, we can share a sample report so you see exactly what’s included.
Yes. If you are deploying artificial intelligence, large language models (LLMs), or AI agents, we test them with the same level of rigor as your other systems.
We focus on AI-specific vulnerabilities, including:
- Prompt injection
- Model and context data leakage
- Jailbreak attacks and guardrail bypasses
- Abuse of connected tools and integrations
- Adversarial attacks
We also help you prepare for compliance with the EU AI Act.
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