From: "M. Edward (Ed) Borasky" <znmeb@...>
Date: 2007-12-10T23:33:33+09:00
Subject: Re: Emulating Netcat and connecting to bind shells

Eduardo Tongson wrote:
> Hello folks,
> 
> I am creating some exploits written in Ruby. Most of my payloads are
> TCP bind shells, Netcat works well for connecting to those bind
> shells. But I thought, why not connect to the shell directly from Ruby
> immediately after sending the payload. Currently I use this snippet
> from a Ruby standard library sample I found somewhere:
> 
> """
> s = TCPsocket.open(host,port)
> STDOUT.flush
> while gets(  )
>   s.write($_)
>   print(s.readline)
> end
> s.close
> """
> 
> Works, but is very limited compared to Netcat. Return only one line
> (for example after an "ls"). One strange thing is that it hangs when I
> send "cd /". No output and subsequent commands are not processed. "/"
> and "cd" are OK. Metasploit has its own library for this kind of
> stuff. I think it is called Metasploit Rex. Looking at the sources I
> see some references to Rex::IO::Stream. I find it complex and I would
> like to avoid something that needs external libraries.
> 
> Can the above snippet be improved? Is there a better way of emulating
> Netcat? Is it possible to use Net::Telnet? Thanks everyone.
> 
>    Eduardo Tongson
> 
> 

I'm not at all familiar with "netcat", but if it's like most open-source 
utilities, it probably has an internal library that you could interface 
directly to Ruby.