Safari improper parse of HTML tags and BlogSpot.com XSS vulnerability

Tuesday, 6 February 2007

Overview:

Safari on occasions may improperly parse the source of an HTML
document, which can lead to the execution of html tags within
comments. This can become dangerous when input filters allow html
tags within comments, as they will get parsed and executed under
certain circumstances.

Details:

In some cases you can cause Apple?s Safari browser to execute code
when it should not be executed. In the following example everything
within the comment, in theory should never be executed; however,
safari decides to execute the script tag.

<title>myblog</title>

Blogs hosted on BlogSpot.com have filter mechanisms for their input;
however, they will allow you to inject anything within comments. This
made it possible to cross site script blogspot.com. Note: Only Safari
viewers will be affected.

Proof of concept: http://dirtybean1234.blogspot.com/

Initial release of vulnerability: http://www.beanfuzz.com/wordpress/?p=99

Vendor Response:

I was unable to get a response from the vendor in regards to this issue

Questions / Comments:
Jose (at) onzra (dot) com

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