RE: Bypassing of web filters by using ASCII


Both of those would work in the case where the charset has
already been set by the server. The problem is that most servers set a
charset by default. The other bigger problem is that both of those (and
the META one) require that you inject HTML into the page to get it to
work. If you can inject a style tag into a page you can embed XSS
See http://ha.ckers.org/xss.html

On Fri, 23 Jun 2006, James C. Slora Jr. wrote:

Amit Klein wrote Thursday, June 22, 2006 3:47 AM

So in order to exploit this in HTML over HTTP, the attacker needs to
either add/modify the Content-Type response header, or to add/modify the
META tag in the HTML page.

There are other ways that might carry a bigger injection threat:

Style ***:
http://msdn.microsoft.com/library/default.asp?url=/workshop/author/dhtml
/reference/properties/charset_1.asp

Object property:
http://msdn.microsoft.com/library/default.asp?url=/workshop/author/dhtml
/reference/properties/charset.asp


By extension, it should also work for inline styles.






-RSnake
http://ha.ckers.org/
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