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APIs are the building blocks of modern applications, enabling communication between systems and services. However, they are also prime targets for attackers. The OWASP API Security Top 10 highlights the most critical API-related security risks and provides actionable guidance to secure APIs effectively.
Broken Object Level Authorization
APIs often expose endpoints that handle object identifiers, creating a broad attack surface for object-level access control issues.
Broken Authentication
Flaws in authentication mechanisms can allow attackers to compromise authentication tokens or exploit implementation weaknesses, leading to unauthorized access.
Broken Object Property Level Authorization
Lack of or improper authorization validation at the object property level can lead to unauthorized information exposure or manipulation.
Unrestricted Resource Consumption
APIs that do not limit resource usage can be exploited, leading to denial of service or increased operational costs.
Broken Function Level Authorization
Complex access control policies and unclear separation between administrative and regular functions can lead to authorization flaws.
Unrestricted Access to Sensitive Business Flows
APIs exposing business flows without considering potential misuse can be exploited, leading to business harm.
Server-Side Request Forgery (SSRF)
APIs fetching remote resources without validating user-supplied URLs can be manipulated to send requests to unintended destinations.
Security Misconfiguration
Improper configurations can open APIs to various attacks, such as exposing unnecessary endpoints or services.
Improper Inventory Management
Lack of proper documentation and inventory of APIs can lead to exposure of deprecated or unsecured API versions.
Unsafe Consumption of APIs
Trusting data from third-party APIs without proper validation can introduce security risks.
OWASP Top 10 APIs: https://owasp.org/www-project-api-security/
You Should Know:
Testing for Broken Object Level Authorization
Use curl to test IDOR vulnerabilities curl -X GET "https://api.example.com/users/1234" -H "Authorization: Bearer <token>" Change the user ID to test unauthorized access curl -X GET "https://api.example.com/users/5678" -H "Authorization: Bearer <token>"
Preventing SSRF Attacks
Use a restricted allowlist for URLs in Node.js
const allowedDomains = ["trusted.com", "safe-api.org"];
if (!allowedDomains.includes(new URL(userInput).hostname)) {
throw new Error("SSRF Attempt Blocked");
}
Rate Limiting for Unrestricted Resource Consumption
Nginx rate limiting configuration
limit_req_zone $binary_remote_addr zone=api_limit:10m rate=10r/s;
location /api/ {
limit_req zone=api_limit burst=20 nodelay;
}
Detecting Security Misconfigurations
Use nmap to scan for open API ports nmap -sV --script=http-vuln <target-ip> -p 80,443,8080
API Inventory Management with OpenAPI
Generate OpenAPI docs using Swagger swagger-cli bundle api-spec.yaml -o openapi.json
What Undercode Say
API security is critical in modern cloud and microservices architectures. Always validate inputs, enforce strict authentication, and monitor API traffic for anomalies. Use tools like OWASP ZAP for automated API security testing:
Run OWASP ZAP baseline scan docker run -v $(pwd):/zap/wrk/:rw -t owasp/zap2docker-stable zap-baseline.py \ -t https://api.example.com -r report.html
For Linux admins, ensure proper logging with journalctl:
journalctl -u your-api-service --since "1 hour ago" --no-pager
Windows admins should audit API access using PowerShell:
Get-WinEvent -LogName "Microsoft-Windows-WebService-Audit" | Where-Object {$_.ID -eq 1000}
Always keep API dependencies updated:
npm audit fix --force For Node.js APIs pip list --outdated For Python APIs
Expected Output:
A hardened API with proper authentication, rate limiting, and continuous security monitoring.
Further Reading:
References:
Reported By: Nett Owasp – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
