This is the writeup about the Bigbasket Open redirect bypass vulnerability.

I tested Bigbasket portal for security loopholes and I picked the main domain as the target.

I fuzzed the domain with tools like wfuzz, ffuf, dirb and using Burp’s Content discovery.

While the fuzz was in progress, I noticed the next= parameter containing a URL, which means I can try Open Redirect / XSS / SSRF issues on this parameter.

I tried open redirection by replacing my domain.

I got Access Denied error which means there is a validation for the domain in the next= parameter.

So as next step I encoded my domain using online HTML encoder.

I URL encoded my domain using this Online tool.

Now I used the URL encoded payload and inserted it on the next= parameter.

After I enter the credentials, and click Login – it redirects to my domain which is a successful Open redirect vulnerability 🎉

Below is the POC video.

POC Video :

💰 I’ve been rewarded by their Security team and acknowledged in their Hall of Fame.

Here’s the Hall of Fame.

Bigbasket Hall of Fame – https://tech.bigbasket.com/security-at-bigbasket/

That’s it in this write up.

Thank you!

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