Wireshark-dev: [Wireshark-dev] [Full-disclosure] Re: Bypassing of web filters by using ASCII (f
From: Joerg Mayer <[email protected]>
Date: Thu, 22 Jun 2006 17:42:57 +0200
The topic is about how ASCII characters with bit 8 set are handled.
I haven't access to my sources right now, so I can't verfiy this.
If this is the case, the right thing to do would be do display any
characters > 0x7F as "undisplayable". 

 Ciao
  Joerg
----- Forwarded message from imipak <[email protected]> -----

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Delivered-To: [email protected]
Date: Thu, 22 Jun 2006 10:31:29 +0100
From: imipak <[email protected]>
To: [email protected], [email protected]
Cc: 
Subject: [Full-disclosure] Re: Bypassing of web filters by using ASCII
Errors-To: [email protected]

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

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----- End forwarded message -----

-- 
Joerg Mayer                                           <[email protected]>
We are stuck with technology when what we really want is just stuff that
works. Some say that should read Microsoft instead of technology.