Application penetration testing consists of controlled simulations of cyberattacks performed by certified specialists to identify vulnerabilities in web and mobile applications in accordance with OWASP and ASVS standards. Virtline conducts penetration tests using black-box, white-box and grey-box methodologies, delivering a report with risk levels and remediation recommendations. Certified to ISO/IEC 27001:2023 by TÜV NORD (certificate AC090 121/2469/6137/2026, valid until 02.2029).
Application penetration testing — web and mobile apps, OWASP and ASVS standards
We conduct penetration tests of web and mobile applications following best practices and standards defined by OWASP (Open Web Application Security Project) and ASVS (Application Security Verification Standard). Our tests help organisations achieve compliance with application protection requirements and identify critical vulnerabilities before attackers can exploit them.
Application security is one of the most important areas of cybersecurity — especially when an application processes personal data, handles financial transactions or serves as the primary customer channel. A penetration test is a controlled attack simulation designed to expose weaknesses before an unauthorised party from outside does.
What do we check in an application penetration test?
The scope is defined individually for each engagement, but we routinely verify the areas with the greatest impact on application security:
Authentication and sessions — resistance to brute-force, weak session tokens, missing expiry, vulnerabilities in password recovery and registration flows.
Access control — checking whether users can reach resources beyond their authorisation (IDOR, horizontal and vertical privilege escalation).
Input validation — SQL, NoSQL and LDAP injection, reflected, stored and DOM-based XSS, SSRF and file-upload vulnerabilities.
API interfaces — REST, SOAP and GraphQL tested for improper authorisation, excessive data exposure and missing rate-limiting.
Server configuration — HTTP security headers, CORS policies, TLS certificates, component versions and administrative interfaces.
Business logic — possibility of bypassing payments, price manipulation, circumventing quantity limits or reusing single-use codes.
Benefits of application penetration testing
Identification of weak points in web and mobile applications before an incident occurs.
Threat detection before a real cyberattack hits the production environment.
Protection of sensitive data — customers’ personal information and databases processed by the application.
GDPR, ISO 27001 and NIS2 compliance — the report serves as evidence of due diligence during audits.
Lower remediation cost — fixing a vulnerability found before deployment is far cheaper than recovering after an incident.
Reputation and customer trust protection for your brand.
How does an application penetration test work — 4 stages
Every engagement is carried out according to a structured methodology aligned with industry standards, ensuring results are reproducible, reliable and comparable over time.
1. Reconnaissance and information gathering — testers build knowledge of the target environment, mapping IP addresses, subdomains, technologies in use, API endpoints and potential entry vectors. We analyse publicly available resources, DNS records, file metadata and HTTP headers.
2. Vulnerability analysis and scanning — automated scanning supported by manual analysis. We verify server configuration, authentication mechanisms, session management and business logic. Vulnerabilities are identified against the OWASP Top 10, with both technical and business risk classified.
3. Exploitation and vulnerability verification — we confirm the real-world exploitability of identified weaknesses through controlled exploitation, without compromising the integrity of production data. We assess opportunities for privilege escalation, lateral movement and data exfiltration. Every attempt is documented with a complete step-by-step record.
4. Reporting and recommendations — the report describes each vulnerability with its risk level (critical, high, medium, low), reproduction steps and a concrete technical recommendation. Vulnerabilities are ranked using the CVSS score. Retesting after remediation is available on request.
Testing methodologies — black-box, grey-box, white-box
The choice of approach depends on the test objective, available resources and the level of trust between the client and the testing team. Each variant provides a different perspective on the application’s security posture.
- Black-box — the tester has no information about the system. Simulates the perspective of an external attacker. Best reflects a realistic intrusion scenario.
- White-box — full access to source code, architecture documentation and configuration. Allows more vulnerabilities to be found in less time. Recommended for pre-deployment audits.
- Grey-box — partial knowledge of the environment, such as a user account or basic API documentation. Combines the realism of black-box with the efficiency of white-box. Most commonly chosen for business applications.
Complementing the OWASP Top 10 is the ASVS standard, which defines three levels of verification requirements: Level 1 (basic, protection against automated attacks), Level 2 (standard, sensitive data, finance and healthcare), Level 3 (advanced, business-critical systems). The target ASVS level is agreed with the client during scope planning.
When to order an application penetration test
A penetration test is particularly recommended in the following situations:
Before public launch of a new application or service
After significant changes to the application architecture or codebase
Before an ISO 27001, SOC 2 or PCI DSS certification audit
After taking over an application from an external supplier
Following a security incident — to assess the scope of the breach
Periodically — at least once a year, regardless of code changes
Frequently asked questions — application penetration testing
How often should application penetration tests be conducted?
We recommend testing at least once a year, and additionally after every significant change to the application code or infrastructure — for example, after deploying new features, migrating to cloud or integrating with an external service provider. Organisations in regulated sectors (finance, healthcare) should consider testing every six months.
How long does an application penetration test take?
Duration depends on the size and complexity of the application. A simple web system can be tested within three to five business days. A complex platform with multiple modules and API interfaces typically requires two to four weeks. A precise schedule is agreed before the project begins.
Do penetration tests disrupt system operations?
We conduct tests in a way that minimises impact on the production environment. For high-availability systems we can work during agreed maintenance windows or on a dedicated staging environment. In both cases the scope and testing methods are agreed with the client in advance.
What is the difference between a vulnerability scan and a penetration test?
A vulnerability scan is an automated tool that identifies potential weaknesses based on a database of known vulnerabilities. A penetration test goes further — the tester manually verifies each finding, attempts to actually exploit it and assesses its real business impact. The test result confirms that a vulnerability exists and can be exploited.
Do penetration tests help with GDPR, ISO 27001 and NIS2 compliance?
Yes. Regular testing is explicitly required or strongly recommended by GDPR (Art. 32), ISO/IEC 27001:2022 (control A.8.8) and the NIS2 Directive (Art. 21). The test report can serve as evidence of due diligence during external audits and regulatory inspections. Virtline holds an ISO/IEC 27001:2023 certificate issued by TÜV NORD.
What does the penetration test report contain?
The report includes an executive summary with a risk level assessment, a detailed description of each vulnerability (OWASP/CVE category, risk level, reproduction steps, potential impact), concrete remediation recommendations with priorities and a proposal for retesting to confirm fixes. On request, a separate management summary can be prepared.
Why Virtline for application penetration testing
Virtline is a team of cybersecurity specialists with extensive experience in penetration testing of web and mobile applications and IT infrastructure. Every project starts with an initial consultation in which we agree the scope, test environment and schedule with the client. We do not use templates — the scope is tailored to the specifics of the system and the industry. Tests are carried out by a dedicated team of at least two specialists, enabling mutual verification of results.
We operate across Europe. We serve both small companies testing their first applications and large organisations in regulated sectors: banking, healthcare, public administration and industry. Our test results are accepted by ISO 27001 auditors, data protection officers and financial sector regulators.
Order an application penetration test and identify vulnerabilities before an outsider does.
ISO/IEC 27001:2023 Certification
Virtline certified by TÜV NORD
Virtline holds the ISO/IEC 27001:2023-08 certificate issued by TÜV NORD. Certificate number: AC090 121/2469/6137/2026, valid until 02.2029.
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