OWASP Testing Guide
  • Foreword by Eoin Keary
  • Frontispiece
  • Introduction
  • The OWASP Testing Framework
    • The Web Security Testing Framework
    • Penetration Testing Methodologies
  • Web Application Security Testing
    • Introduction and Objectives
    • Information Gathering
      • Conduct Search Engine Discovery Reconnaissance for Information Leakage (WSTG-INFO-01)
      • Fingerprint Web Server (WSTG-INFO-02)
      • Review Webserver Metafiles for Information Leakage (WSTG-INFO-03)
      • Enumerate Applications on Webserver (WSTG-INFO-04)
      • Review Webpage Content for Information Leakage (WSTG-INFO-05)
      • Identify Application Entry Points (WSTG-INFO-06)
      • Map Execution Paths Through Application (WSTG-INFO-07)
      • Fingerprint Web Application Framework (WSTG-INFO-08)
      • Fingerprint Web Application (WSTG-INFO-09)
      • Map Application Architecture (WSTG-INFO-10)
    • Configuration and Deployment Management Testing
      • Test Network Infrastructure Configuration (WSTG-CONF-01)
      • Test Application Platform Configuration (WSTG-CONF-02)
      • Test File Extensions Handling for Sensitive Information (WSTG-CONF-03)
      • Review Old Backup and Unreferenced Files for Sensitive Information (WSTG-CONF-04)
      • Enumerate Infrastructure and Application Admin Interfaces (WSTG-CONF-05)
      • Test HTTP Methods (WSTG-CONF-06)
      • Test HTTP Strict Transport Security (WSTG-CONF-07)
      • Test RIA Cross Domain Policy (WSTG-CONF-08)
      • Test File Permission (WSTG-CONF-09)
      • Test for Subdomain Takeover (WSTG-CONF-10)
      • Test Cloud Storage (WSTG-CONF-11)
      • Testing for Content Security Policy (WSTG-CONF-12)
    • Identity Management Testing
      • Test Role Definitions (WSTG-IDNT-01)
      • Test User Registration Process (WSTG-IDNT-02)
      • Test Account Provisioning Process (WSTG-IDNT-03)
      • Testing for Account Enumeration and Guessable User Account (WSTG-IDNT-04)
      • Testing for Weak or Unenforced Username Policy (WSTG-IDNT-05)
    • Authentication Testing
      • Testing for Credentials Transported over an Encrypted Channel (WSTG-ATHN-01)
      • Testing for Default Credentials (WSTG-ATHN-02)
      • Testing for Weak Lock Out Mechanism (WSTG-ATHN-03)
      • Testing for Bypassing Authentication Schema (WSTG-ATHN-04)
      • Testing for Vulnerable Remember Password (WSTG-ATHN-05)
      • Testing for Browser Cache Weaknesses (WSTG-ATHN-06)
      • Testing for Weak Password Policy (WSTG-ATHN-07)
      • Testing for Weak Security Question Answer (WSTG-ATHN-08)
      • Testing for Weak Password Change or Reset Functionalities (WSTG-ATHN-09)
      • Testing for Weaker Authentication in Alternative Channel (WSTG-ATHN-10)
      • Testing Multi-Factor Authentication (MFA) (WSTG-AUTH-11)
    • Authorization Testing
      • Testing Directory Traversal File Include (WSTG-ATHZ-01)
      • Testing for Bypassing Authorization Schema (WSTG-ATHZ-02)
      • Testing for Privilege Escalation (WSTG-ATHZ-03)
      • Testing for Insecure Direct Object References (WSTG-ATHZ-04)
      • Testing for OAuth Authorization Server Weaknesses
      • Testing for OAuth Client Weaknesses
      • Testing for OAuth Weaknesses (WSTG-ATHZ-05)
    • Session Management Testing
      • Testing for Session Management Schema (WSTG-SESS-01)
      • Testing for Cookies Attributes (WSTG-SESS-02)
      • Testing for Session Fixation (WSTG-SESS-03)
      • Testing for Exposed Session Variables (WSTG-SESS-04)
      • Testing for Cross Site Request Forgery (WSTG-SESS-05)
      • Testing for Logout Functionality (WSTG-SESS-06)
      • Testing Session Timeout (WSTG-SESS-07)
      • Testing for Session Puzzling (WSTG-SESS-08)
      • Testing for Session Hijacking (WSTG-SESS-09)
      • Testing JSON Web Tokens (WSTG-SESS-10)
    • Input Validation Testing
      • Testing for Reflected Cross Site Scripting (WSTG-INPV-01)
      • Testing for Stored Cross Site Scripting (WSTG-INPV-02)
      • Testing for HTTP Verb Tampering (WSTG-INPV-03)
      • Testing for HTTP Parameter Pollution (WSTG-INPV-04)
      • Testing for Oracle
      • Testing for MySQL
      • Testing for SQL Server
      • Testing PostgreSQL
      • Testing for MS Access
      • Testing for NoSQL Injection
      • Testing for ORM Injection
      • Testing for Client-side
      • Testing for SQL Injection (WSTG-INPV-05)
      • Testing for LDAP Injection (WSTG-INPV-06)
      • Testing for XML Injection (WSTG-INPV-07)
      • Testing for SSI Injection (WSTG-INPV-08)
      • Testing for XPath Injection (WSTG-INPV-09)
      • Testing for IMAP SMTP Injection (WSTG-INPV-10)
      • Testing for File Inclusion
      • Testing for Code Injection (WSTG-INPV-11)
      • Testing for Command Injection (WSTG-INPV-12)
      • Testing for Buffer Overflow (WSTG-INPV-13)
      • Testing for Format String Injection (WSTG-INPV-13)
      • Testing for Incubated Vulnerability (WSTG-INPV-14)
      • Testing for HTTP Splitting Smuggling (WSTG-INPV-15)
      • Testing for HTTP Incoming Requests (WSTG-INPV-16)
      • Testing for Host Header Injection (WSTG-INPV-17)
      • Testing for Server-side Template Injection (WSTG-INPV-18)
      • Testing for Server-Side Request Forgery (WSTG-INPV-19)
      • Testing for Mass Assignment (WSTG-INPV-20)
    • Testing for Error Handling
      • Testing for Improper Error Handling (WSTG-ERRH-01)
      • Testing for Stack Traces (WSTG-ERRH-02)
    • Testing for Weak Cryptography
      • Testing for Weak Transport Layer Security (WSTG-CRYP-01)
      • Testing for Padding Oracle (WSTG-CRYP-02)
      • Testing for Sensitive Information Sent via Unencrypted Channels (WSTG-CRYP-03)
      • Testing for Weak Encryption (WSTG-CRYP-04)
    • Business Logic Testing
      • Introduction to Business Logic
      • Test Business Logic Data Validation (WSTG-BUSL-01)
      • Test Ability to Forge Requests (WSTG-BUSL-02)
      • Test Integrity Checks (WSTG-BUSL-03)
      • Test for Process Timing (WSTG-BUSL-04)
      • Test Number of Times a Function Can Be Used Limits (WSTG-BUSL-05)
      • Testing for the Circumvention of Work Flows (WSTG-BUSL-06)
      • Test Defenses Against Application Misuse (WSTG-BUSL-07)
      • Test Upload of Unexpected File Types (WSTG-BUSL-08)
      • Test Upload of Malicious Files (WSTG-BUSL-09)
      • Test Payment Functionality (WSTG-BUSL-10)
    • Client-Side Testing
      • Testing for Self DOM Based Cross-Site Scripting
      • Testing for DOM-Based Cross Site Scripting (WSTG-CLNT-01)
      • Testing for JavaScript Execution (WSTG-CLNT-02)
      • Testing for HTML Injection (WSTG-CLNT-03)
      • Testing for Client-side URL Redirect (WSTG-CLNT-04)
      • Testing for CSS Injection (WSTG-CLNT-05)
      • Testing for Client-side Resource Manipulation (WSTG-CLNT-06)
      • Testing Cross Origin Resource Sharing (WSTG-CLNT-07)
      • Testing for Cross Site Flashing (WSTG-CLNT-08)
      • Testing for Clickjacking (WSTG-CLNT-09)
      • Testing WebSockets (WSTG-CLNT-10)
      • Testing Web Messaging (WSTG-CLNT-11)
      • Testing Browser Storage (WSTG-CLNT-12)
      • Testing for Cross Site Script Inclusion (WSTG-CLNT-13)
      • Testing for Reverse Tabnabbing (WSTG-CLNT-14)
    • API Testing
      • Testing GraphQL (WSTG-APIT-01)
  • Reporting
    • Reporting
    • Vulnerability Naming Schemes
  • Appendix
    • Testing Tools Resource
    • Suggested Reading
    • Fuzz Vectors
    • Encoded Injection
    • History
    • Leveraging Dev Tools
  • Testing Checklist
  • Table of Contents
  • REST Assessment Cheat Sheet
  • API Testing
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On this page
  • Background Concepts
  • How to Test
  • Generic Testing Method
  • Specific Testing – (Token-Based) Authentication
  • Related Test Cases
  • Tools
  • References

API Testing

PreviousREST Assessment Cheat Sheet

Last updated 2 years ago

Web APIs have gained a lot of popularity as they allow third-party programs to interact with websites in a more efficient and easy way. In this guide, we will discuss some basic concepts about APIs and the way to test security for APIs.

Background Concepts

REST (Representational State Transfer) is an architecture that is implemented while developer design APIs. Web application APIs following the REST style are called REST API. REST APIs use URIs (Uniform Resource Identifiers) to access resources. The generic URI syntax as defined in as below:

URI = scheme "://" authority "/" path [ "?" query ] [ "#" fragment ]

We are interested in the path of URI as the relationship between user and resources. For example, https://api.test.xyz/admin/testing/report, this shows report of testing, there is relationship between user admin and their reports.

The path of any URI will define REST API resource model, resources are separated by a forward slash and based on Top-Down design. For example:

  • https://api.test.xyz/admin/testing/report

  • https://api.test.xyz/admin/testing/

  • https://api.test.xyz/admin/

REST API requests follow the defined in

Methods
Description

GET

Get the representation of resource’s state

POST

Create a new resource

PUT

Update a resource

DELETE

Remove a resource

HEAD

Get metadata associated with resource’s state

OPTIONS

List available methods

REST APIs use the response status code of HTTP response message to notify the client about their request’s result.

Response Code
Response Message
Description

200

OK

Success while processing client's request

201

Created

New resource created

301

Moved Permanently

Permanent redirection

304

Not Modified

Caching related response that returned when the client has the same copy of the resource as the server

307

Temporary Redirect

Temporary redirection of resource

400

Bad Request

Malformed request by the client

401

Unauthorized

Client is not allowed to make requests or access a particular resource

402

Forbidden

Client is forbidden to access the resource

404

Not Found

Resource doesn't exist or incorrect based on the request

405

Method Not Allowed

Invalid method or unknown method used

500

Internal Server Error

Server failed to process request due to an internal error

HTTP headers are used in requests and responses. While making API requests, Content-Type header is used and is set to application/json because the message body contains JSON data format.

Web authentication types are based on:

  • Bearer Tokens: Identified by the Authorization: Bearer <token> header. Once a user logs in, they are provided with a bearer token that is sent on every request in order to authenticate and authorize the user to access OAuth 2.0 protected resources.

  • Basic HTTP authentication: Identified by the Authorization: Basic <base64 value> header. Once a user is trying to login, the request is sent with the mentioned header containing the a base64 value, having its content as username:password. This is one of the weakest forms of authentication as it transmits the username and password on every request in an encoded manner, which can be easily retrieved.

How to Test

Generic Testing Method

Step 1: List endpoint and make different request method: Login with user profile and use a spider tool to list the endpoints of this role. To examine the endpoints, you will need to make different request methods and observe how the API behaves.

Step 2: Exploit bugs - As know how to list endpoints and examine endpoints with HTTP methods at step 1, we will find some way to exploit bug. Some testing strategies are below:

  • IDOR testing

  • Privilege escalation

Specific Testing – (Token-Based) Authentication

Token-based authentication is implemented by sending a signed token (verified by the server) with each HTTP request.

Related Test Cases

Tools

  • ZAProxy

  • Burp suite

References

HTTP Cookies: Identified by the Cookie: <name>=<unique value> header. On user login success, the server replies with a Set-Cookie header specifying its name and unique value. On every request, the browser automatically appends it to the requests going to that server, following .

The most commonly used token format is the JSON Web Token (JWT), defined in . The guide contains further details on how to test JWTs.

All test cases

RFC3986
HTTP Request Methods
RFC7231
SOP
RFC7519
Testing JSON Web Tokens
IDOR
Privilege escalation
Session Management
Testing JSON Web Tokens
REST HTTP Methods
RFC3986 URI
JWT
Cracking JWT