REST APIs
Endpoint-by-endpoint testing of CRUD operations, query parameters, path parameters, HTTP method handling, content-type negotiation and response filtering against the OWASP API Security Top 10.
API Security Testing Services
API Security Testing Services: REST, GraphQL & OWASP API Top 10
APIs are the primary attack surface for modern applications, and the risks differ fundamentally from traditional web vulnerabilities. Broken Object-Level Authorization (BOLA), broken authentication, mass assignment, excessive data exposure and missing rate limiting are the issues that let attackers access other users' data, escalate privileges and abuse business logic at scale. CipherTrivia's API security testing services cover the full OWASP API Security Top 10 across REST, GraphQL, gRPC and event-driven architectures, with fix-ready reports and a free retest once remediation is complete.
- 0
- OWASP API Top 10 categories tested
- 0h
- Avg. critical-finding response
- 1
- Free retest included
api-security-scan.live
Scanning
Client
POST
/api/v2/users//profile
Auth
Bearer eyJhbG...kpXVCJ9
Weak JWT
Gateway
rate_limit: none cors: *
No Rate Limit
Endpoint
user.id == req.params.id? SKIP
BOLA
Response
200 OK { "name": "...", "email": "...", "ssn": "***-**-1234", "role": "admin" }
2 Critical
2 High
Aligned to the standards your auditors expect
OWASP API Top 10
OAuth 2.0 & OIDC
OpenAPI / Swagger
CVSS 4.0 Scoring
PCI DSS
// What's Included
What's Included in Our API Security Testing Services
API security testing requires a fundamentally different approach from web application testing. Endpoints have no UI, authorization logic is spread across middleware and business layers, and the data surface is whatever the serializer returns, not what a front end chooses to display. Our API security testing services are built around these realities, covering four core areas that account for the majority of critical API findings.
// Scope
What Our API Security Testing Services Cover
Our API security testing services cover every protocol and integration pattern your engineering team ships. Most engagements start with the customer-facing REST or GraphQL layer and expand to internal services, webhooks and third-party integrations over time.
GraphQL APIs
Introspection control, query depth and complexity limits, batched query abuse, alias-based rate-limit bypass, field-level authorization, and mutation-specific access control testing.
gRPC & WebSocket
Protobuf message tampering, service method enumeration, bidirectional stream abuse, WebSocket origin validation, message injection and connection lifecycle testing.
OAuth 2.0 & OIDC Flows
Authorization code flow, PKCE implementation, token exchange, scope escalation, redirect URI validation, state parameter handling and token storage security across all grant types.
Webhook & Event-Driven APIs
Signature verification, replay attack resistance, payload injection, callback URL validation and event ordering abuse for webhook receivers, message queues and event-driven integrations.
Third-Party API Integrations
Secret management for API keys and tokens, error-handling paths that leak upstream credentials, SSRF through integration endpoints, and trust-boundary analysis where your application relays data from external services.
// What We Find
Common Vulnerabilities Our API Security Testing Services Find
The OWASP API Security Top 10 defines the vulnerability categories that matter most for APIs. Here are six of the highest-impact classes we test for across every API security testing engagement, and what makes each one difficult to catch without manual, context-aware testing.
Class 01 / 06
Broken Object-Level Authorization (BOLA)
Broken Object-Level Authorization (BOLA)
BOLA is the most common critical finding in API security assessments. The vulnerability occurs when an API endpoint accepts an object identifier (user ID, order ID, document ID) and returns or modifies that object without verifying that the authenticated user has permission to access it. The pattern is straightforward: User A's token is used to request User B's data by changing an ID in the URL or request body, and the server complies because it trusts the token but never checks ownership.
Why it's missed
Scanners cannot reason about object ownership. Finding BOLA requires testing every sensitive endpoint with two real accounts of different privilege levels side by side, which is exactly how our testers work across every endpoint in scope.
Broken Authentication
API authentication failures go well beyond weak passwords. JWTs accepted with alg: none or signed with a weak shared secret, refresh tokens that remain valid after logout or password change, missing token expiration enforcement, and password-reset tokens that are predictable or reusable are the patterns we find most often. The entire authentication chain, from initial credential exchange to token refresh to logout invalidation, needs to be tested as a single flow.
Why it's missed
Most testing stops at the login endpoint. We test the full token lifecycle: issuance, refresh, revocation, cross-environment replay, and edge cases like concurrent sessions and password-reset race conditions.
Broken Object Property Level Authorization
This class combines two related problems: excessive data exposure (the API returns more fields than the client needs, including PII, internal IDs or financial data) and mass assignment (the API accepts and persists fields that should be read-only, such as role, isAdmin, accountBalance or plan). Both stem from the same root cause: the serializer trusts the schema rather than explicitly defining which fields are readable and writable per role.
Why it's missed
The front end only displays a subset of the API response, so excess fields are invisible in the UI. We inspect raw response bodies field by field and attempt to write back every field we receive to test for mass assignment.
Unrestricted Resource Consumption
APIs without proper rate limiting on authentication endpoints allow credential-stuffing and OTP brute-force attacks. Missing limits on resource-intensive operations (search queries, report generation, file uploads, bulk exports) enable denial-of-service through legitimate-looking requests. GraphQL APIs are particularly vulnerable: deeply nested queries, alias-based batching and unrestricted query complexity can exhaust backend resources with a single request.
Why it's missed
Rate limits often exist on the gateway but can be bypassed with header manipulation, IP rotation or parameter variation. We test the actual enforcement, not just the documented policy.
Broken Function-Level Authorization (BFLA)
BFLA occurs when a regular user can invoke administrative endpoints by guessing or discovering the URL pattern. The API correctly authenticates the user but fails to check whether their role permits the requested action. Common patterns include predictable admin paths (/api/admin/users), HTTP method confusion (a regular user can DELETE a resource they can only GET), and internal endpoints that were never intended to be externally reachable but are.
Why it's missed
Admin endpoints are often excluded from client documentation and therefore from testing. We enumerate every method on every endpoint from the OpenAPI spec and server routes, then test each one with every role in scope.
Server-Side Request Forgery (SSRF)
Any API feature that fetches a URL on the server's behalf is a potential SSRF vector: webhook registration, file import by URL, link preview generation, PDF rendering, and integration callback URLs. In cloud deployments, SSRF can reach the instance metadata endpoint (169.254.169.254) and retrieve temporary IAM credentials, turning a URL-fetching feature into full cloud account compromise. Internal service endpoints, databases, and admin interfaces become reachable from outside.
Why it's missed
Blind SSRF produces no visible response in the API output. We use out-of-band detection infrastructure to confirm every URL-handling feature, including ones that appear harmless like avatar uploads and import endpoints.
0+
Avg. findings per API engagement
0%
Findings retested at no cost
0h
Avg. response on critical findings
0
OWASP API Top 10 categories covered
// Methodology
How Our API Security Testing Process Works
A typical API security testing engagement runs one to three weeks. Five phases, executed in order, every time.
Phase 01 · Week 0
API Discovery & Documentation Review
We import your OpenAPI/Swagger specs, GraphQL schemas, or Postman collections and map every endpoint, method, parameter and role. If documentation is incomplete, we supplement with traffic analysis and endpoint enumeration to build a complete attack-surface inventory before testing begins.
OpenAPI Import
GraphQL Introspection
Endpoint Enumeration
output
# Phase 01: Discovery
$ import-schema api.yaml
→ 142 endpoints mapped
→ 6 roles identified
→ 23 params accept user IDs
✓ Attack surface ready
// Deliverables
What You Receive From Our API Security Testing Services
Every API security testing engagement ends with documentation built to be used: by engineers fixing authorization logic, by architects reviewing API design patterns, and by auditors verifying due diligence.
01
Executive Summary
Non-technical overview of the API security posture, overall risk rating, and the business impact of key findings, written for leadership and compliance teams.
02
Detailed Findings Report
Every finding listed with CVSS 4.0 score, OWASP API Top 10 mapping, proof-of-concept HTTP requests and responses, and step-by-step reproduction instructions.
03
Remediation Guidance
Developer-ready fix guidance with code-level recommendations, middleware patterns and API gateway configuration changes mapped to each finding.
04
Live Walkthrough Session
A call with our testers to walk through every finding, demonstrate exploitation, answer engineering questions and agree on a remediation plan.
05
Free Retest & Closure Report
Once findings are fixed, we retest every one at no extra cost and issue a signed closure report confirming remediation for auditors, customers or regulators.
Five deliverables. One engagement. Everything your team and your auditors need.
See a sample report// Why CipherTrivia
Why Choose CipherTrivia for API Security Testing
A few things set how we run API security testing engagements apart from vendors who treat APIs as an afterthought bolted onto web application testing.
API-First Testing Methodology
We test at the HTTP layer, not through a browser. Every endpoint is tested directly with crafted requests, which is how attackers interact with your API and why UI-based testing misses most API vulnerabilities.
Senior Testers on Every Engagement
No junior-only teams running default scanner profiles. Every BOLA, BFLA and authentication finding is manually validated by an experienced tester before it reaches your report.
Zero False-Positive Noise
If it's in your report, it's exploitable. We don't pad findings with unvalidated scanner output, so your engineering team spends time fixing authorization logic, not triaging noise.
Compliance-Ready Reports
Reports map directly to PCI DSS, SOC 2, ISO 27001 and HIPAA evidence requirements. Findings reference OWASP API Top 10 and CWE identifiers so there is no rework before your audit.
// Proof of Work
An API Security Testing Case Study
API Security · Banking & Fintech
Closing Critical Gaps in a Banking API Gateway
A regional bank needed a full API security assessment of its customer-facing API gateway ahead of launch. We tested 140+ endpoints across REST and webhook integrations, found 14 issues including a critical BOLA flaw and missing rate limiting on the authentication flow, and retested every fix before a 3-week deadline.
Read case study// FAQ
Frequently Asked Questions About API Security Testing
What is included in an API security test?
An API security test covers authentication and authorization logic, object-level access control (BOLA), function-level access control (BFLA), mass assignment, rate limiting, input validation, data exposure in responses, and business-logic abuse. Every finding is mapped to the OWASP API Security Top 10 and scored with CVSS 4.0, with proof-of-concept requests and remediation guidance included.
Do you test GraphQL APIs differently from REST APIs?
Yes. GraphQL introduces attack surface that does not exist in REST: introspection exposure, query depth and complexity abuse, batched query attacks, alias-based rate-limit bypass, and field-level authorization gaps in nested resolvers. We test all of these in addition to the standard OWASP API Top 10 categories (BOLA, BFLA, broken auth, etc.) that apply to any API architecture.
How do you test APIs that have no user interface?
We work directly at the HTTP layer using your OpenAPI or GraphQL schema, Postman collections, or raw endpoint documentation. Testing is performed with Burp Suite, custom scripts and API-specific fuzzing frameworks. A user interface is not required. In fact, testing without a UI is how we catch the issues the UI hides: over-fetched response fields, mass-assignment vectors and undocumented endpoints.
Can API security testing be done on production?
Yes, with agreed rules of engagement. We coordinate testing windows, respect rate limits, avoid destructive operations (no DELETE on real data), and use dedicated test accounts. Where possible we recommend a staging environment that mirrors production, but production testing is common and safe when scoped correctly. We agree on all boundaries before testing begins.
Is the retest included in the engagement cost?
Yes. Every API security testing engagement includes one full retest cycle at no additional cost. Once your team has remediated the findings, we re-verify each issue individually and issue a signed closure report confirming what was fixed. This is the document most auditors and enterprise customers ask for directly.
Get Started With API Security Testing
Tell us about your API architecture, endpoints and authorization model, and we will scope an API security testing engagement that fits your timeline and budget.