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Stored XSS at exchange.onavo.com

A stored XSS vulnerability found on exchange.onavo.com during security research

Upon sub-domain enumeration I found this sub-domain exchange.onavo.com

It was some outdated app, and some fun for me

Though it was quite an app (while I didn’t quite understand the purpose), All it had was simple feature of creating something called “Child”

Created a child with name : [script>alert(1);</script> And BAM ! XSS

But it’s a self XSS and I didn’t see any share feature in the app

Then I remembered a weird login process the app had. Login page had only one input field “email”

You enter an email id and you get an email in your inbox with a link You click the link and you get logged in !

Something like this : http://exchange.onavo.com/signin/79ada86f556da28ab358dcea3e7d664579a52

Anyways, This gave me an Idea

I could give this login link to anyone. When he visits it the XSS is triggered and I could steal the cookies scoped to *.parse.com

The XSS was fixed by Facebook Security Team

This post is licensed under CC BY 4.0 by the author.