An API can correctly authenticate a user while still allowing that user to access another customer's information.
For UK organisations operating SaaS platforms, mobile applications, digital services or enterprise integrations, API security testing needs to examine the rules behind every request — not just whether a login succeeds. NuageSEC assesses REST, GraphQL, SOAP and gRPC APIs using automated analysis and expert manual testing.
Browsers, iOS/Android & 3rd-party consumers
Routing, rate limits & authentication layer
Business workflows & object-level authorisation
Databases, customer records & cloud storage
This means an API authorisation weakness may affect data, workflows or functions across several applications. APIs often connect:
Web portals, admin consoles, and single-page applications.
iOS and Android client backends handling sensitive user workflows.
Serverless functions, containerised workloads, and cloud storage.
Partner APIs, payment gateways, and data sharing pipelines.
Core ERP, CRM, billing, and internal identity management systems.
Service-to-service internal communication and remote procedure calls.
Staff-facing tools and administrative workflows built on internal APIs.
Operating critical REST, GraphQL, or microservice APIs?Let our security team evaluate your endpoints, object authorisation, and data boundaries.
NuageSEC's current API service identifies these testing areas and supports public, internal, partner and cloud-based API environments.
OAuth, JWT, authentication workflows and related controls.
Object-level and function-level access control.
Whether one authenticated user can access another user's or tenant's resources.
Whether legitimate workflows can be manipulated to produce unintended outcomes.
Whether API responses disclose information beyond what the requester should receive.
Whether controls adequately restrict abusive or excessive requests.
Public, internal, partner and relevant undocumented endpoints within scope.
Relevant API gateway, transport, headers and deployment controls.
NuageSEC currently identifies all four API technologies among supported testing environments.
Authentication, authorisation, object access and input security.
Schema exposure, authorisation, excessive queries and business logic.
Enterprise and legacy integrations, XML security and message integrity.
Service-to-service communication and cloud-native API security.
For organisations processing personal data, security obligations are risk-based. The ICO states that appropriate technical and organisational measures should protect personal data and that organisations should regularly test security measures as appropriate. Its guidance includes protection against common web vulnerabilities and appropriate vulnerability scanning and penetration testing.
An API assessment can be useful where APIs form part of the technical environment through which personal data is processed. It does not, by itself, establish UK GDPR compliance.
For a multi-tenant UK SaaS application, testing should answer:
Can Tenant A access Tenant B's objects?
Can a lower-privileged user invoke administrative functionality?
Are object identifiers properly authorised?
Do API responses expose unnecessary fields?
Can business workflows be manipulated?
Are partner and internal APIs enforcing the same security assumptions?
NuageSEC's API methodology specifically addresses object-level authorisation, function-level authorisation, tenant isolation and business logic.
Share the API endpoints, protocols, and documentation (OpenAPI / Swagger, Postman, GraphQL schema). Our team will respond with a tailored assessment scope within 24 hours.
Tell us about your REST, GraphQL, SOAP, or gRPC APIs — our security engineers will respond within 24 hours.
NuageSEC's published API security materials document assessment coverage for authentication, authorisation, business logic, data protection and configuration, with executive reporting, technical findings, evidence, remediation and retesting.
Its published USA healthcare case study is relevant as international evidence: broken access control, IDOR and sensitive data exposure resulted in an attack path to patient records. This case is labelled as USA evidence, not UK experience.
NuageSEC's current API service states alignment with the OWASP API Security Top 10, OWASP ASVS, the OWASP Testing Guide and the OpenAPI Specification, alongside other security frameworks.
Framework alignment should guide the assessment without replacing architecture-specific analysis and business-logic testing.
NuageSEC's published API service specifically describes executive reports, technical documentation and retesting.
A comprehensive inventory of relevant tested APIs, endpoints, methods, and parameters.
Detailed vulnerability descriptions, affected endpoints, and architectural context.
Full technical proof, HTTP requests/responses, and reproduction steps supporting each finding.
Severity and exploitability scoring calibrated to your business impact.
Actionable recommendations and code-level patch guidance specific to API implementation.
A business-focused summary for stakeholders alongside the technical findings.
Independent verification of fixes, where retesting is included in scope.
Review our published API penetration testing findings: View the API Sample Report
Direct answers to questions UK engineering and security leaders ask about API security assessments.
It is an authorised assessment of APIs for vulnerabilities involving authentication, authorisation, data access, business logic, input handling, configuration and other security controls.
Yes. BOLA/IDOR is explicitly covered in NuageSEC's API security testing materials and sample report.
Yes. GraphQL is explicitly included in NuageSEC's current API security coverage.
Yes. NuageSEC's published API material includes public, partner, internal and microservice API environments.
Yes. NuageSEC's API methodology includes business-logic assessment of multi-step workflows.
Yes, where retesting is included in the engagement.
Identify authorisation gaps, data-exposure risks and business-logic weaknesses before they become a route to sensitive information or critical functionality.
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Tell us about your REST, GraphQL, SOAP, or gRPC APIs — our engineers respond within 24 hours.