Difference between revisions of "REST Security Cheat Sheet"
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= Introduction =
= Introduction =
Revision as of 13:45, 31 July 2012
DRAFT CHEAT SHEET - WORK IN PROGRESS
REST or REpresentational State Transfer is a means of expressing specific entities in a system by URL path elements, REST is not an architecture but it is an architectural style to build services on top of the Web. REST allows interaction with a web-based system via simplified URL's rather than complex request body or POST parameters to request specific items from the system. This document serves as a guide (although not exhaustive) of best practices to help REST-based services.
Check Authorization for User-Specific Entities
While REST is useful for targeting specific entities in the system, the URL itself should not be the only authorizing token for sensitive entities (such as account transactions, personally-identifying information, etc.). Proper authentication should take place, and the token for authorization should be sent as a cookie. Furthermore, no Personally-Identifiable Information (such as bank-account number, credit card number, etc.) should be used as a parameter to request an entity. See the [DOR (Direct Object Reference) Prevention Cheat Sheet] for strategies for preventing Direct Object Reference weaknesses.
Whitelist-Only Response Types
It is common for REST services to allow multiple response types (e.g. application/xml or application/json, and the client specifies the preferred order of response types by the Accept header in the request. Do NOT simply copy the Accept header to the Content-type header of the response. Reject the request (ideally with a 406 Not Acceptable response) if the Accept header does not specifically contain one of the allowable types.
Because there are many MIME types for the typical response types, it's important to document for clients specifically which MIME types should be used.
Whitelist Allowable Methods
It is common with RESTful services to allow multiple methods for a given URL for different operations on that entity. For example, a GET request might read the entity while POST would update an existing entity, PUT would create a new entity, and DELETE would delete an existing entity. It is important for the service to properly restrict the allowable verbs such that only the allowed verbs will work, all others return a proper response code (for example, a 403 Forbidden).
In Java EE in particular, this can be difficult to implement properly. See Bypassing Web Authentication and Authorization with HTTP Verb Tampering for an explanation of this common misconfiguration.
Authentication for a REST-based service should not take place by passing the user ID and password in path elements of the URL. URL's are commonly cached by browsers, proxies, etc. so sensitive information should not be included directly in the URL.
OWASP Cheat Sheets Project Homepage
Developer Cheat Sheets (Builder)
- Authentication Cheat Sheet
- Choosing and Using Security Questions Cheat Sheet
- Clickjacking Defense Cheat Sheet
- C-Based Toolchain Hardening Cheat Sheet
- Cross-Site Request Forgery (CSRF) Prevention Cheat Sheet
- Cryptographic Storage Cheat Sheet
- DOM based XSS Prevention Cheat Sheet
- Forgot Password Cheat Sheet
- HTML5 Security Cheat Sheet
- Input Validation Cheat Sheet
- JAAS Cheat Sheet
- Logging Cheat Sheet
- .NET Security Cheat Sheet
- Password Storage Cheat Sheet
- Pinning Cheat Sheet
- Query Parameterization Cheat Sheet
- Ruby on Rails Cheatsheet
- REST Security Cheat Sheet
- Session Management Cheat Sheet
- SQL Injection Prevention Cheat Sheet
- Transport Layer Protection Cheat Sheet
- Unvalidated Redirects and Forwards Cheat Sheet
- User Privacy Protection Cheat Sheet
- Web Service Security Cheat Sheet
- XSS (Cross Site Scripting) Prevention Cheat Sheet
Assessment Cheat Sheets (Breaker)
Mobile Cheat Sheets
OpSec Cheat Sheets (Defender)
Draft Cheat Sheets
- OWASP Top Ten Cheat Sheet
- Access Control Cheat Sheet
- Application Security Architecture Cheat Sheet
- Business Logic Security Cheat Sheet
- PHP Security Cheat Sheet
- Secure Coding Cheat Sheet
- Secure SDLC Cheat Sheet
- Threat Modeling Cheat Sheet
- Web Application Security Testing Cheat Sheet
- Grails Secure Code Review Cheat Sheet
- IOS Application Security Testing Cheat Sheet
- Key Management Cheat Sheet
- Insecure Direct Object Reference Prevention Cheat Sheet
- Content Security Policy Cheat Sheet
Authors and Primary Editors
First Last - first.last [at] owasp.org