To People who don’t know me , I Ashutosh Mishra , 3rd Year Btech Computer Science Student, A cybersecurity Researcher by day and bug hunter by night,Mainly love to find Business logic bugs(Account Takeover and SSRF).
Hello everyone this is my second account takeover write up , hope all you have read the first one, if not you can read here. This account takeover was done Three months before on december 2020 , but the response and award came on Feb 2021
Lets Begin , I was searching for a financial websites to hunt , after searching for good time on google , I got a website which was running the bug bounty program . for security purposes lets take the website name redacted.com
This time before starting the burp suite , I started to understand the application flow as the normal user, then I started to spider the website using burp suite , I was searching for some endpoints to find SSRF , but after hunting 3 Hours I could not find any endpoints for successful ssrf.
The next thing which come to my mind is going for the registration and the login page of the website, I tried to put the collaborator link in every request for blind ssrf ,but no success.
As, I am a guy who always look for the ssrf and account takeover , spending around 3 days on the target , got some little hanging fruits, but i was not happy to report , then I started to hunt on login page ,there was two option to login , normal email and password and other was through the oauth , I tried to find oauth misconfiguration , but developers were quite good in implementing the oauth, now next try was to login through email and password with response manipulation , but no success.
It was the time where I was tired and was going to sleep at 2 am , but my eyes went on reset password, so i thought to give a last try on this mechanism,
The reset password was implemented by sending the email instructions to reset password, while requesting the reset password I intercepted the request to response hoping to get the reset token in response but got nothing.
so after I went to my mail , and opened up the reset link and tried to intercept the request while changing the password , i saw the following request
After observing the following request two things came to my mind , one no csrf protection was implemented in the request, but I thought the authenticity_token might be chained with email address(so there will be no use of csrf) so to checked whether the token and email are linked or not , I changed the mail from firstname.lastname@example.org to email@example.com and suddenly something happens , which made me shocked.
There was a notification on right corner , claiming that password has been reseted . To actually confirm it I tried to enter the victim email address and my password and Boom Boom we are inside the victim account , so there was no chaining of authentication token with email address which lead me to account takeover of anyone
Bug Reported: 8 December 2020
Bug Triaged: 11 February 2021
Bounty Rewarded: $2000
Tip: Try to checked token whether it is chained to accounts or not by changing the parameter value
Feel Free to message on Instagram any queries related to bug bounty
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