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Account Takeover by Chaining Two IDORs

Welcome back to another writeup. In this write-up i am going to tell you how i chained two IDORs together to achieve an Account Takeover of any user with no interaction. In 2021 i only hacked on two programs. Both were similar in nature. I submitted 99 bugs on one program where i hacked for 4-5 months and its where i found this bug. The program is about helpdesk with different users roles. There were three different roles which were Admin, Manager and user. Admin manages all the stuff, manager have all the access except the organizations settings and the user can only do what he was assigned to do.

An admin can creates different departments and assign them to different managers. Deparments have different characteristics like new hire, salaries, projects etc. An admin can add new users to organization and also can edit those users. He can changes their email addresses, change passwords and lockout their accounts. These are the two places where i found two IDORs.

The first IDOR i got when assigning a department to any manager. The flow was something like that, first you will create a new depmartment. Then you will add a manager into it. When you add a manager into it and click on save, the manager ID will be passed in the request. So simply changing my manager ID to another organziation manager's ID will add that manager into my department. It was a simple easy IDOR with no much impact. This will add manager of another organziation into my organization's department. why someone would give access of his own deparment to someone else. I tried to add myself into another organization's department by chainging the depmartment ID but unfortunately it didnt work.

I thought i will submit it if i couldnt find anything else today because you can spam user by adding them to alot of departments, still better then not finding anything. I wrote it down and moved onto testing other parts of the website. I went to user edit settings where an admin can change users email and password. I tried to change password of my manager and captured the request in Burp. I saw its ID in the request which i changed with manager of my second account and the response was 200. I was able to login into that manager account with the new password. I was happy but the IDOR was pretty simple and i thought it will be a dup. But dup or not it was a p1 so i was going to submit it asap.

I turned on my screen recording and started reproducing the bug but when i tried to change the password of another org's manager it gave me 403. I tried it multiple times but it was giving me 403 instead of 200. I turned off the screen recording and started figuring out why it worked before. When i first changed the password of a manager i used the ID of a manager which i added into my deparmtent. But during video PoC i tried to change the password of a manager which wasnt added into any of my deparment.

In order to change password of any user first i have to add him into my own department using the first IDOR. Then i will be able to change his password by going into my user settings and replacing its ID with one of my own manager. I quicky wrote a nice report and submitted it with video PoC. After few days it got triagged and accpeted as P1. The first IDOR was pretty simple so is the second but for second IDOR to work you have to perform first IDOR.

If you have any feedback or any question feel free to dm me on twitter R29k.Thank you for reading this, i will see you in the next write up.