API12019: Testing for IDOR/Broken object level authorization:

Difficulty: Easy

Tips: Don't blindly test for changing numbers till you get PII, tools can do this for you. Dive deep into applications, find hidden functionality and features, and know how your application works most of all to succeed in finding IDOR's.

Finding IDOR Attack Vectors Ideas:

  1. What do they use for authorization?(JWT, API Keys, cookies, tokens) Tip: Find this out by replacing high privaledge authorization with lower privaledge authorization and seeing what the server responds with
  2. Understand how they use ID's, hashes, and their API. Do this by looking at the API Documentations if they have one.

Recon for IDOR's:

Note: Recon for IDORs is very hard, many of them are found manually using logic and they depend on each application highly. To add onto this, IDOR's are commonly found on API endpoints with JSON parameters, not URL. However, IDOR recon is still good to possibly find some low-hanging fruit.

Every time you see a new API endpoint that receives an object ID from the client, ask yourself the following questions:

Bypassing Object Level Authorization: