How I could Delete Instagram Captions and Comments that are not mine,.....

Its been a while since i published my last post. So, here i come with a write up for chaining of multiple issues in Facebook Acquisition - Instagram, that could allowed me to delete entire comments/captions from the Instagram DB.

Instagram Web and mobile Applications

For the first 2 hours or so, I could not find anything as each request is added with a signature and I am lazy enough not to understand/reverse the signature logic. So as usual, i was about the close my Mac and then, saw a request without signature.

request without a signature

Bingo..something to play around. so i started working on the request, trying to find most common bugs, like sqli,xss, csrf etc.. Then to cross verify a csrf issue, I used my browser. But to my surprise, in later requests in browser app, there is no signature at all, but of-course csrf issue is properly protected.

So while testing with both the App and Browser together, I realised that there is an authorisation flaw in the comment deletion action. But it requires certain comment ID values, which are (supposed to be) not available for comments other than your's.. So basically, you can not delete other's comments as you wont be having other's comment IDs (such a nice logic).

request used for deleting comments

So i went back through the 10mb of all my burp logs to find, if the comment ids are leaked somewhere. And bingo, there is an api which shows comment ids of all the comments of a picture.

request that fetches comment ids

So now we have all the elements needed to do some DAMAGE....

url :     https://www.instagram.com/web/comments/<phto id>/delete/<comment/description id>/

photo id & owner id: to extract the ids of the target photos/comments, make a GET call to

https://www.instagram.com/<target username>/

comment/description id : to extract the comment id of the target comment, make a GET call to

https://i.instagram.com/api/v1/media/<photo id>_<owner id>/comments/

Now is the time to Delete some comments.... simply make a POST call with web app cookies to

https://www.instagram.com/web/comments/<photo id>/delete/<comment id>/

(but don't forget to add the csrf token into headers) and Done.. we have successfully deleted the target comment.

A better and easy (different way of enumeration of necessary information) to exploit the same bug is given in the below video demonstration.

After playing around the api for some more time, i realised that there is no rate limiting applied on the Delete api. 

So i made a small python script which will make a call to target instagram user account to fetch all the photo ids. Then it will make another request to fetch all the comment ids on each photo id. Then finally it will make requests to delete each comment on each photo, there by deleting all comments and captions ever added on any photo of the target user.

deleting all comments on all photos of target user

Thanks for reading/watching... And as usual, suggestions and queries are always welcome.