Security Basics mailing list archives

HTTP tunneling to bypass proxy filter


From: "uglyhunK" <uglyhunK () hippiecluB org>
Date: Sat, 19 Apr 2008 19:09:01 +0530


Recently I was challenged by network admin to bypass corporate HTTP proxy
filter. Easier option would have been to download one of many HTTP tunnel
clients but that is ruled out as all the sites are blocked. I didn't want to
email the installation file as there is a strict monitoring policy to using
email and "leaving no traces" is one of the primary conditions.

Only option left was to write my own HTTP tunneling client and being a
developer I have access to JDK. Server component is written in PHP and it
works like a charm; all the communication is encoded in base64 (though not
the best way to obfuscate data). It took me just 10 days to successfully
bypass the proxy filter and access literally all the websites except https
ones. Just for the info, this is @ one of the largest American banks. So, I
won the first round and now I threw a challenge @ him to identify this kinda
of tunneled data and block it successfully.

I'm not sure if he can do this, but, would like to know from you guys if
there is any way for the admin to block me from using custom tunnel client.


-uglyhunK






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