Web Application Penetration Testing Services
At Trilight Security, we provide comprehensive web application penetration testing services for organizations across the USA and the EU, including a strong focus on Germany. Our certified experts simulate real-world attacks against your web applications — from customer-facing portals and e-commerce platforms to internal SaaS tools and API-driven microservices — uncovering exploitable vulnerabilities that automated scanners routinely miss. Get in touch with Trilight Security to discover how our web application pentesting services can strengthen your application security, protect your users’ data, and demonstrate compliance with applicable regulations.
Authenticated Testing
We conduct testing as both unauthenticated users and authenticated users across different privilege levels — standard users, privileged users, and administrators — to ensure that access controls and authorization logic are enforced correctly at every layer. This approach surfaces vulnerabilities such as insecure direct object references, privilege escalation paths, and broken function-level access control that are invisible to unauthenticated assessments.
API Security Testing
Modern web applications are API-driven by design. We assess REST, GraphQL, and SOAP APIs as a dedicated component of every web application engagement — testing for broken object level authorization, excessive data exposure, lack of rate limiting, mass assignment vulnerabilities, and injection flaws in API endpoints. API security is tested both in isolation and in the context of the application’s full request flow.
Our Offering
Black Box Pentesting
We provide black box penetration testing services where we have no prior knowledge of the application’s internal architecture, source code, or technology stack. We interact with the application exclusively through its exposed interfaces, replicating the perspective of an external attacker with no insider access.
Grey Box Pentesting
We conduct grey box pentests where we have limited info about the target — such as technology stack, API docs, or a set of user credentials — but without access to source code or full architecture docs. This approach reflects the realistic threat posed by an attacker with partial access through credential theft or else.
White Box Pentesting
We conduct white box pentests where we have full access to source code, architecture docs, API specifications, and credentials across all user roles. This approach enables the deepest possible assessment of application logic, data flow security, and access control implementation.
Why Web Application Penetration Testing?
Web applications are the primary attack surface for most organisations — handling authentication, payments, sensitive user data, and business-critical logic that automated scanners can identify only in part. Broken access control is the most prevalent web application vulnerability class, appearing in 94% of tested applications according to OWASP data, yet it is one of the categories that automated tools cover least effectively, because no scanner can understand data ownership or business logic on its own. A manual web application penetration test goes beyond running an automated scanner — our experts map the full attack surface, chain vulnerabilities together, probe business logic for abuse paths, and demonstrate real exploitability with proof-of-concept evidence. By identifying these weaknesses proactively, we help you prevent data breaches and account takeovers, protect payment and PII-handling flows, satisfy requirements under GDPR, PCI-DSS, NIS2, and ISO/IEC 27001, and build trust with customers and enterprise partners who require independent security validation.
What We Test
Application Layer Vulnerabilities
Our web application assessments provide systematic coverage of all major vulnerability classes, aligned to the OWASP Top 10 (2025):
- Broken Access Control (A01) — IDOR, missing function-level access control, forced browsing, path traversal, privilege escalation
- Security Misconfiguration (A02) — HTTP security headers, server configuration, exposed admin interfaces, default credentials, verbose error disclosure
- Software Supply Chain Failures (A03) — vulnerable and outdated third-party components, dependency confusion, known CVEs in bundled libraries
- Cryptographic Failures (A04) — weak encryption, plaintext transmission of sensitive data, insecure key management, weak TLS configuration
- Injection (A05) — SQL, NoSQL, command, LDAP, XPATH, SSTI, and Cross-Site Scripting (XSS)
- Insecure Design (A06) — business logic flaws, missing abuse-case controls, workflow bypass vulnerabilities
- Authentication Failures (A07) — brute force, credential stuffing, weak session tokens, MFA bypass, JWT weaknesses, OAuth misconfigurations
- Data Integrity Failures (A08) — insecure deserialisation, unsigned update mechanisms, CI/CD pipeline tampering
- Security Logging & Alerting Failures (A09) — insufficient audit logging, missing alerting for authentication anomalies
- Mishandling of Exceptional Conditions (A10) — error messages leaking sensitive data, improper exception handling, edge-case abuse
API Security
API testing is aligned to the OWASP API Security Top 10 (2023), covering broken object level authorization (BOLA), broken authentication, broken object property level authorization, unrestricted resource consumption, broken function level authorization, unrestricted access to sensitive business flows, SSRF, security misconfiguration, improper inventory management, and unsafe consumption of APIs.
Penetration Testing Process
We use a combination of manual techniques and automated tooling to simulate real-world attacks against web applications. Our methodology is adapted to the specific technology stack, authentication model, and business context of each application. Typically, web application penetration testing projects include the following stages:
- Information Gathering & Reconnaissance: We map the full attack surface of the application — enumerating endpoints, parameters, authentication mechanisms, technology stack, third-party integrations, and exposed APIs. For black box assessments this includes passive OSINT, DNS enumeration, and technology fingerprinting. For grey and white box assessments we supplement this with API specification review and architecture analysis to ensure complete coverage before active testing begins.
- Configuration & Infrastructure Review: We assess web server and application server configuration for security misconfigurations — including HTTP security headers (CSP, HSTS, X-Frame-Options), TLS/SSL configuration and cipher strength, exposed administrative interfaces, verbose error messages, and directory listing. We review cloud hosting and CDN configurations where applicable.
- Authentication & Session Management Testing: We test all authentication mechanisms for weakness — including brute-force and credential stuffing resistance, MFA implementation and bypass potential, password policy enforcement, account lockout behaviour, and session token security. Session management is assessed for predictable tokens, insecure storage, improper expiry, and session fixation vulnerabilities.
- Authorisation & Access Control Testing: We systematically test whether the application enforces correct access controls for every function and data object — attempting to access resources belonging to other users (IDOR), reach privileged functionality as a standard user, and bypass access controls through parameter tampering, HTTP method manipulation, and forced browsing to unlisted endpoints.
- Input Validation & Injection Testing: We test all input vectors for injection vulnerabilities — including SQL injection, NoSQL injection, command injection, LDAP injection, XML/XPATH injection, Server-Side Template Injection (SSTI), and Cross-Site Scripting (XSS). Blind and out-of-band injection techniques are applied where direct feedback is not available. All exploitation attempts are controlled and non-destructive.
- Business Logic Testing: Automated scanners cannot detect flaws in application-specific workflows. We manually probe the logic that governs your application's core functionality — including multi-step checkout and payment flows, transaction processing, role and entitlement management, referral and discount systems, and any feature involving financial value or privileged data. This phase targets vulnerabilities such as workflow bypass, race conditions, parameter tampering to manipulate prices or account balances, and abuse of application-specific trust assumptions.
- API Security Testing: We assess REST, GraphQL, and SOAP API endpoints for the full OWASP API Security Top 10 (2023) — including broken object level authorization (BOLA/IDOR), broken authentication, excessive data exposure, lack of resource and rate limiting, broken function level authorization, mass assignment, security misconfiguration, improper asset management, and insufficient logging. GraphQL-specific testing includes introspection abuse, batching attacks, and field-level authorization bypass.
- Client-Side Security Testing: We assess client-side security controls including Cross-Site Request Forgery (CSRF) protection, clickjacking resistance, DOM-based XSS, insecure use of postMessage, open redirects, and sensitive data exposure in JavaScript source and browser storage (localStorage, sessionStorage, cookies).
- Reporting: Our reports are thorough, developer-friendly, and written to be useful for both technical teams and executive stakeholders. Each report includes:
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- A detailed attack narrative describing how each vulnerability could be exploited and what an attacker could achieve, helping your team understand the real-world risk of each finding.
- Specific, prioritised remediation recommendations for every identified vulnerability, with code-level guidance where applicable, ordered by risk severity and exploitability.
- Compliance mapping to OWASP Top 10 (2025), OWASP API Security Top 10 (2023), OWASP WSTG, NIST, PCI-DSS, GDPR, NIS2, and other applicable frameworks.
Our Benefits
Top Certifications
Our experts have deep skills proven by years of success in demanding enterprise environments and top industry certifications such as OSCE, OSCP, eWPTXv2, eWPT, BSCP (Burp Suite Certified Practitioner), CREST, CEH, and others.
Top Methodologies
OWASP Web Security Testing Guide (WSTG), OWASP Top 10 (2025), OWASP API Security Top 10 (2023), PTES (Penetration Testing Execution Standard), NIST SP 800-115, TLPT and others.
Rich Deliverables
We provide pentest reports with detailed findings, attack narratives, PoC evidence, remediation recommendations with code-level guidance, compliance mapping, and other content tailored to the customer’s needs.
Cost Efficiency
We have access to top-tier cybersecurity and application security talent with extensive experience in demanding enterprise environments — delivered at competitive, transparent pricing.
Penetration Testing Methodologies
Our web application penetration testing services follow the OWASP Web Security Testing Guide (WSTG v4.2) as the primary testing methodology, providing structured coverage across information gathering, configuration and deployment management testing, identity management testing, authentication testing, authorisation testing, session management testing, input validation testing, error handling, cryptography testing, business logic testing, client-side testing, and API security testing. Vulnerability findings are classified and prioritised using the OWASP Top 10 (2025) and OWASP API Security Top 10 (2023).
The overall engagement structure follows PTES (Penetration Testing Execution Standard), and technical documentation for compliance-driven engagements is aligned to NIST SP 800-115. Findings are mapped to MITRE ATT&CK techniques where applicable. For compliance engagements, we align reporting to PCI-DSS requirements 6.2.3 and 11.3, NIS2 Article 21, ISO/IEC 27001, GDPR, HIPAA, DORA, and SOC 2 as required by the client.
Tools
Our experts tailor their toolset based on the engagement type — black box, grey box, or white box — and the specific technology stack of the target application. Burp Suite Professional is the primary tool for manual interception, request manipulation, and active scanning throughout every engagement. Automated scanning and template-based vulnerability detection is performed with Nuclei. Web server and configuration assessment uses Nikto and testssl.sh for TLS analysis. Directory and parameter discovery relies on ffuf and Gobuster. SQL injection testing is augmented with sqlmap. Subdomain and asset enumeration uses Subfinder and Amass. API endpoint discovery and crawling is conducted with Katana. All automated findings are manually reviewed and validated by experienced testers — no automated output is reported without human verification of exploitability and impact.
Our Certifications
Deliverables
- Executive Summary: A high-level overview of the assessment results and overall risk exposure, written for management and non-technical stakeholders, including a clear statement of the most critical findings and their potential business impact.
- Test Plan: A document outlining the agreed scope, objectives, testing methodology, rules of engagement, and timeline for the engagement.
- Detailed Technical Report: A comprehensive report documenting all findings, including vulnerability descriptions aligned to OWASP Top 10 and API Security Top 10 categories, CVSS risk ratings, step-by-step proof-of-concept exploitation walkthroughs, and prioritised remediation guidance — including code-level fix recommendations where applicable.
- Vulnerability Assessment: A full inventory of all vulnerabilities identified during the engagement, including affected endpoints, parameter details, severity ratings, and exploitability assessment.
- Evidence: Screenshots, HTTP request and response captures, and other supporting artefacts for all findings, providing reproducible documentation of every vulnerability.
- Compliance Mapping: A structured mapping of findings and remediation recommendations to applicable frameworks including OWASP Top 10 (2025), OWASP API Security Top 10 (2023), PCI-DSS, NIS2, GDPR, ISO/IEC 27001, and others as required.
- Action Plan: A structured remediation roadmap with recommended actions, suggested timelines, and responsible parties for each identified issue.
A presentation or briefing for relevant stakeholders — including a summary of findings, risk exposure, and recommended next steps — can be prepared upon request. After a follow-up retest to confirm that all identified vulnerabilities have been remediated, we issue a Pentest Certificate, which can be used for compliance audits, vendor due diligence, and customer communications.
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About Web Application Penetration Testing
Penetration Test Report Sample
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FAQ
Web application penetration testing is a security assessment in which our experts simulate real-world attacks against your web application — probing authentication, access controls, input handling, business logic, and API security — to identify exploitable vulnerabilities before malicious actors do.
Vulnerability scanning is an automated process that identifies known weaknesses using signature-based detection. Web application penetration testing goes further: our experts actively attempt to exploit identified vulnerabilities, probe business logic for abuse paths that no scanner can detect, chain multiple weaknesses together to demonstrate realistic attack scenarios, and provide verified proof-of-concept evidence for every finding. Automated tools cannot test access control logic, business workflow vulnerabilities, or multi-step attack chains — these require human expertise.
We test all types of web applications including traditional multi-page applications, single-page applications (SPAs built on React, Angular, Vue, and other frameworks), REST and GraphQL APIs, e-commerce platforms, SaaS applications, customer portals, internal tools, content management systems, and microservice architectures. Both publicly accessible and internally hosted applications can be assessed.
Our process covers reconnaissance and attack surface mapping, authentication and session management testing, access control and authorisation testing, input validation and injection testing (SQL, XSS, SSTI, command injection, and others), business logic analysis, API security assessment, client-side security testing, and configuration review — all conducted manually by experienced testers, supported by purpose-built tooling.
The OWASP Top 10 is the most widely referenced standard for web application security risk, published by the Open Web Application Security Project and updated regularly based on real-world vulnerability data. The 2025 edition identifies Broken Access Control, Security Misconfiguration, Software Supply Chain Failures, Cryptographic Failures, and Injection as the top five risk categories. Our web application penetration testing provides systematic coverage of all ten categories — plus the OWASP API Security Top 10 for API-heavy applications.
Yes. API testing is a core component of every web application engagement, not an optional add-on. We test REST, GraphQL, and SOAP APIs against the full OWASP API Security Top 10 (2023), covering broken authorization at the object and function level, authentication weaknesses, excessive data exposure, rate limiting, mass assignment, and security misconfiguration. API endpoints are assessed both in isolation and in the context of the application’s full business logic.
Our web application penetration testing follows the OWASP Web Security Testing Guide (WSTG), OWASP Top 10 (2025), OWASP API Security Top 10 (2023), and PTES. For compliance-driven engagements, we align findings and documentation to PCI-DSS (requirements 6.2.3 and 11.3), NIS2 Article 21, ISO/IEC 27001, GDPR, HIPAA, DORA, and SOC 2 as applicable.
Yes. For applications in scope for PCI-DSS, we conduct assessments that satisfy PCI-DSS Requirement 6.2.3 (bespoke and custom software security review) and Requirement 11.3 (penetration testing). Our reports include the compliance mapping and technical documentation that QSAs require during PCI-DSS audits. We have experience testing payment flows, cardholder data environments, and payment gateway integrations.
Testing is conducted in a controlled manner within agreed rules of engagement. We strongly recommend conducting assessments against a staging or pre-production environment wherever possible. Where production testing is required, we work within defined parameters — avoiding destructive operations, excessive load generation, and any actions that could affect real user data — and we maintain ongoing communication throughout the engagement to address any concerns immediately.
Yes, and we strongly recommend it. Identifying security issues during development is significantly less costly than remediating them post-launch. Early-stage testing can cover architecture review, authentication design, and access control model validation — identifying structural weaknesses before they are built into the application. We support testing at any stage from early beta through to pre-launch.
Duration depends on the size and complexity of the application, the number of user roles and privilege levels, the number of API endpoints in scope, and the depth of testing required. A typical engagement for a standard web application ranges from five to fifteen business days. We provide a detailed scoping estimate prior to any engagement.
For black box testing we require only the application URL, confirmation of scope, and a statement of authorisation. For grey box testing we typically also need user credentials for each role in scope and any available API documentation. For white box testing we additionally require access to source code repositories and architecture documentation. All information is handled in accordance with our ISO 27001-aligned security practices.
We recommend testing at least annually, and additionally after significant new feature releases, changes to authentication or payment flows, migration to new infrastructure, or prior to major compliance audits. Many compliance frameworks — including PCI-DSS, NIS2, and ISO/IEC 27001 — mandate regular application security testing. For applications with frequent release cycles, we can support recurring assessment models aligned to your development cadence.
Yes. Our web application penetration tests can be scoped and documented to satisfy requirements under PCI-DSS, GDPR, NIS2, HIPAA, DORA, ISO/IEC 27001, SOC 2, and other applicable regulatory and contractual frameworks. We provide compliance-mapped reporting that aligns findings and remediation guidance directly to the relevant control requirements.
Yes. Our team is available to consult on remediation efforts, clarify findings, review proposed fixes, and provide code-level guidance on secure implementation. Once remediation is complete, we conduct a focused retest to confirm that all identified vulnerabilities have been effectively resolved before issuing the Pentest Certificate.
Pricing depends on the size and complexity of the application, the number of user roles in scope, the depth of API testing required, and whether source code review is included. Engagements typically start from €1,500–1,800 for focused assessments, scaling with application complexity and scope — a proportionate investment compared to the cost of a data breach, which averaged over €4 million per incident in Europe in 2024. Contact us for a detailed, obligation-free quote tailored to your application and compliance requirements.
Our Recognition
