kryndex / api-security-checklist

Checklist of the most important security countermeasures when designing, testing, and releasing your API

API Security Checklist

Checklist of the most important security countermeasures when designing, testing, and releasing your API.

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Authentication

• Don't use Basic Auth Use standard authentication (e.g. JWT, OAuth).
• Don't reinvent the wheel in Authentication, token generating, password storing use the standards.

JWT (JSON Web Token)

• Use random complicated key (JWT Secret) to make brute forcing token very hard.
• Don't extract the algorithm from the payload. Force algorithm in the backend (HS256 or RS256).
• Make token expiration (TTL, RTTL) short as possible.
• Don't store sensitive data in the JWT payload, it can be decoded easily.

OAuth

• Always validate redirect_uri on server side to allow only whitelisted URLs.
• Always try to exchange for code not tokens (don't allow response_type=token).
• Use state parameter with a random hash to prevent CSRF on OAuth authentication process.
• Define default scope, and validate scope parameter for each application.

Access

• Limit requests (Throttling) to avoid DDoS / Bruteforce attacks.
• Use HTTPS on server side to avoid MITM.
• Use HSTS header with SSL to avoid SSL Strip attack.

Input

• Use proper HTTP method according to operation , GET (read), POST (create), PUT (replace/update) and DELETE (to delete a record).
• Validate content-type on request Accept header ( Content Negotiation ) to allow only your supported format (e.g. application/xml , application/json ... etc) and respond with 406 Not Acceptable response if not matched.
• Validate content-type of posted data as you accept (e.g. application/x-www-form-urlencoded , multipart/form-data ,application/json ... etc ).
• Validate User input to avoid common vulnerabilities (e.g. XSS, SQL-Injection , Remote Code Execution ... etc).
• Don't use any sensitive data ( credentials , Passwords, security tokens, or API keys) in the URL, but use standard Authorization header.

Processing

• Check if all endpoint protected behind the authentication to avoid broken authentication.
• User own resource id should be avoided. Use /me/orders instead of /user/654321/orders
• Don't use auto increment id's use UUID instead.
• If you are parsing XML files, make sure entity parsing is not enable to avoid XXE.
• Use CDN for file uploads.
• If you are dealing with huge amount of data, use Workers and Queues to return response fast to avoid HTTP Blocking.
• Do not forget and leave the DEBUG mode on.

Output

• Send X-Content-Type-Options: nosniff header.
• Send X-Frame-Options: deny header.
• Send Content-Security-Policy: default-src 'none' header.
• Force content-type for your response , if you return application/json then your response content-type is application/json.
• Don't return sensitive data like credentials , Passwords, security tokens.
• Return the proper status code according to the operation completed. (e.g. 200 OK , 400 Bad Request , 401 Unauthorized, 405 Method Not Allowed ... etc).

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Contribution

Feel free to contribute , fork -> edit -> submit pull request. For any questions drop us an email at [email protected].