David Sopas – Web Security Researcher

html5

11/01/17 Tips and Tricks # , , , ,

Meter HTML5 XSS filter bypass

I was playing around with some new HTML5 features and noticed a funny one.

Meter gives you a cool progress bar on-the-fly – https://developer.mozilla.org/en-US/docs/Web/HTML/Element/meter

Immediately I thought about using it to bypass some WRONG blacklist tags XSS filter and add a event to it:

<meter onmouseover="alert(1)"

You can check it on https://jsfiddle.net/btksfbbx/

Nowadays this doesn’t make any advantage to a researcher because you can use arbitrary tags:

<sopas style=font-size:200px onmouseover=alert(1)>Sopas

Online – https://jsfiddle.net/thnwcjcx/

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14/01/16 Tips and Tricks # , ,

201 event handlers supported by modern browsers

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