Full Disclosure mailing list archives

Re: Bypassing of web filters by using ASCII

From: imipak <imipak () gmail com>
Date: Thu, 22 Jun 2006 10:31:29 +0100

Hi,

2. affected software

Only the InternetExplorer displays ASCII encoded web pages as 7 bit. We
checked several hardware router and antivirus solutions, all of which
failed to detect malicious JavaScript in manipulated web pages.



Ethereal (I can't bring myself to call it 'wireshark' yet) seems to be
vulnerable to the same problem. This is from the 'follow TCP stream'
dialog, showing the request and response for the PoC page:


GET /ASCII HTTP/1.1

Host: www.iku-ag.de

User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.0.4)
Gecko/20060504 Firefox/1.5.0.4

Accept: text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5

Accept-Language: en,en-us;q=0.5

Accept-Encoding: gzip,deflate

Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7

Keep-Alive: 300

Connection: keep-alive

Cache-Control: max-age=0



HTTP/1.1 200 OK

Server: Apache-Coyote/1.1

Content-Type: text/html;charset=US-ASCII

Transfer-Encoding: chunked

Date: Thu, 22 Jun 2006 09:21:54 GMT



c3

<html><head><title>ASCII Test</title></head><body><div style="border:
2px solid; padding: 5px; margin-left: 10px; background-color:
#ffffc0;">.......................................</body></html>

0




Hmmm, I just noticed Firefox's Accept-Charset header doesn't include
ASCII. Does the HTTP spec say that ASCII is the default charset?

/i

_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/

Current thread:

Re: Bypassing of web filters by using ASCII imipak (Jun 22)
- Re: Bypassing of web filters by using ASCII Kurt Huwig (Jun 22)