An API can authenticate the correct user and still authorise the wrong object.
APIs increasingly connect German applications, SaaS platforms, enterprise systems, cloud environments, mobile applications and third-party integrations. The important security question is: Can every user access only the data and functions they are actually authorised to use? NuageSEC provides API security testing across REST, GraphQL, SOAP and gRPC environments, combining automated analysis with expert manual testing.
Browsers, mobile apps & enterprise client platforms
Routing, rate limits & authentication layer
Business workflows & tenant-level authorisation
Databases, customer records & cloud repositories
API security requires examining how authentication, authorisation, logic and data exposure interact under realistic attacker manipulation.
Validating OAuth 2.0, OIDC flows, JWT signatures, API tokens and session controls under hostile manipulation.
Testing object-level (BOLA/IDOR) and function-level (BFLA) access controls across all roles and tenants.
Assessing whether legitimate multi-step API workflows can be manipulated to trigger unauthorised outcomes.
Identifying endpoints exposing excessive personal, financial or corporate data beyond the caller's entitlement.
NuageSEC's API security testing explicitly covers 8 technical areas, supporting public, internal, partner and microservice-based API architectures.
OAuth, OIDC, JWTs, API keys and authentication/session handling across all client types.
Object-level and function-level access controls to prevent horizontal and vertical privilege escalation.
Validating whether a legitimate user can manipulate object references to access another user's or tenant's resources.
Assessing whether legitimate API workflows can be manipulated to create unintended outcomes or bypass approval rules.
Identifying cases where API responses expose more information than the requester should receive.
Testing throttling, abuse resistance and resource-consumption protections under sustained stress.
Identifying authorised public, internal, partner and relevant undocumented endpoints.
Reviewing gateway policies, transport encryption, CORS headers, schema enforcement and deployment controls.
NuageSEC tests across modern and enterprise API protocols, tailoring testing techniques to each protocol's specific architecture.
Test authentication, authorisation, input handling and data access across RESTful microservices and monoliths.
Assess schema exposure, authorisation, excessive query behaviour, field-level access and business logic.
Assess enterprise and legacy API interfaces and relevant XML/message-security controls.
Assess service-to-service authentication, authorisation and cloud-native communication controls.
In multi-tenant SaaS environments, testing must determine whether strict isolation holds across every tenant, user role and partner integration.
Can Tenant A access Tenant B's objects?
Testing whether data filters, tenant IDs and token claims strictly isolate multi-tenant SaaS environments.
Can standard users invoke administrative functions?
Validating whether unprivileged accounts can invoke administrative endpoints, export functions or billing tools.
Are object identifiers correctly authorised?
Verifying that every direct object reference (ID, GUID, hash) is checked against the caller's active session.
Are sensitive fields properly restricted?
Ensuring responses do not expose internal IDs, tenant metadata or sensitive customer data to standard callers.
Do business workflows enforce intended state changes?
Evaluating whether multi-step checkout, verification, onboarding or approval workflows can be skipped.
Do partner APIs enforce appropriate security boundaries?
Testing whether third-party webhooks, B2B integrations and external API keys are isolated from internal systems.
Technical API security testing provides measurable evidence that supports governance and compliance obligations across Europe.
For organisations processing personal data, Article 32 GDPR requires technical and organisational security measures appropriate to the risk and specifically includes regular testing, assessment and evaluation of security effectiveness.
Where APIs process personal data, API security testing provides technical verification regarding unauthorized access, broken authorisation, excessive data exposure, authentication weaknesses and insecure integrations.
Important note: This is technical evidence—not a standalone GDPR compliance determination.
For organisations subject to the German NIS2/BSIG framework, §30 BSIG includes vulnerability management, security in the acquisition/development/maintenance of systems, risk-management effectiveness assessment and access control.
API security testing can contribute technical evidence to these risk-management activities where APIs form part of the relevant information systems and connected services.
API assessments validate that technical controls withstand deliberate exploitation attempts.
Automated tooling can identify endpoints and known syntax flaws. Expert manual testing determines whether complex business logic and authorisation hold under attack.
Manual testing validates whether the requesting role is entitled to the object and whether direct object references cross tenant boundaries.
Testing evaluates whether multi-step API workflows can be manipulated to create state changes, bypass payments or approve unauthorized actions.
Evaluating whether two separate, legitimate API endpoints can be combined by an attacker into an unintended high-impact exploit chain.
NuageSEC presents technical sample reports and published international case evidence demonstrating real-world API assessment capability.
Our published API sample report demonstrates the exact technical depth delivered to clients:
NuageSEC published an in-depth API security assessment for a healthcare platform. Testing identified broken access control, IDOR and sensitive data exposure leading to unauthorized access to patient records.
Note: This case study is explicitly USA customer evidence, presented transparently as proof of offensive API testing methodology.
NuageSEC's current API assessment materials describe executive risk summaries, technical findings, PoC evidence, remediation guidance and independent retesting.
Structured catalog of all identified, tested, public, internal and undocumented API endpoints.
Granular vulnerability documentation with affected endpoints, parameters, schemas and reproduction steps.
Validated proof-of-concept evidence, HTTP payloads and exploitation transcripts proving real impact.
CVSS scores calibrated to your organisation's real operational exposure and business criticality.
Clear contextual explanation of what each technical finding means for customer trust and data security.
In-depth identification of underlying flaws in code, schema enforcement or gateway architecture.
Actionable, code-level recommendations, framework-specific fixes and gateway configuration patches.
Rigorous verification of developer fixes and updated attestation documentation where retesting is scoped.
Tell NuageSEC about your REST, GraphQL, SOAP or gRPC APIs and security objectives.
Tell us about your API endpoints and architecture — our security team will respond within 24 hours.
Direct answers to common questions German organisations ask about API security testing.
It is an authorised assessment of APIs for weaknesses in authentication, authorisation, business logic, data protection, configuration and related controls.
Yes, where the APIs are within the authorised assessment scope.
Yes. BOLA/IDOR is explicitly covered in NuageSEC's API testing materials.
Yes. GraphQL is included in NuageSEC's current API security coverage.
Yes. Both are included in NuageSEC's current API coverage.
Yes, where authorised and included within scope.
It can provide technical security evidence and remediation information, but it does not independently establish NIS2 compliance.
Identify broken authorisation, tenant-isolation weaknesses, sensitive-data exposure and business-logic vulnerabilities before they become an entry point into critical systems.
Explore German services & other markets
Tell us about your API endpoints and architecture — our security team will respond within 24 hours.