Comments on: Bash socket programming with /dev/tcp http://thesmithfam.org/blog/2006/05/23/bash-socket-programming-with-devtcp-2/ Your blog is probably better than mine. Thu, 18 Mar 2010 14:19:44 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: Vladimir http://thesmithfam.org/blog/2006/05/23/bash-socket-programming-with-devtcp-2/comment-page-1/#comment-99683 Vladimir Wed, 10 Mar 2010 22:03:50 +0000 http://thesmithfam.org/blog/?p=21#comment-99683 I have adjusted this code to write and read from a non-web server. The problem is that my msg_out is 94 bytes, but server gets 95. I wonder where the extra byte is coming from. #~ Open socket. exec 3/dev/tcp/172.26.0.6/9991 # 103, 6 #~ Send msg. echo "$msg_out" >&3 #~ Receive msg. read -r msg_in <&3 echo "msg_in: $msg_in" Please give me you thoughts. Regards, Vladimir. San Jose, CA. I have adjusted this code to write and read from a non-web server.
The problem is that my msg_out is 94 bytes, but server gets 95.
I wonder where the extra byte is coming from.

#~ Open socket.
exec 3/dev/tcp/172.26.0.6/9991 # 103, 6

#~ Send msg.
echo “$msg_out” >&3

#~ Receive msg.
read -r msg_in <&3
echo "msg_in: $msg_in"

Please give me you thoughts.
Regards,
Vladimir.
San Jose, CA.

]]> By: Dave http://thesmithfam.org/blog/2006/05/23/bash-socket-programming-with-devtcp-2/comment-page-1/#comment-88768 Dave Thu, 01 Oct 2009 21:02:10 +0000 http://thesmithfam.org/blog/?p=21#comment-88768 Brian: By "bashism", I didn't mean to say that it was exclusive to bash, just that the file /dev/tcp does not actually exist in any file system. --Dave Brian: By “bashism”, I didn’t mean to say that it was exclusive to bash, just that the file /dev/tcp does not actually exist in any file system.

–Dave

]]> By: Brian K. White http://thesmithfam.org/blog/2006/05/23/bash-socket-programming-with-devtcp-2/comment-page-1/#comment-88765 Brian K. White Thu, 01 Oct 2009 20:50:10 +0000 http://thesmithfam.org/blog/?p=21#comment-88765 Not a bashism at all. Similar functionality is in at least ksh (real ksh) and zsh. Not a bashism at all.
Similar functionality is in at least ksh (real ksh) and zsh.

]]> By: debian38 http://thesmithfam.org/blog/2006/05/23/bash-socket-programming-with-devtcp-2/comment-page-1/#comment-86959 debian38 Tue, 08 Sep 2009 17:50:49 +0000 http://thesmithfam.org/blog/?p=21#comment-86959 Why is it not enabled in Debian ? Because bash in Debian is compiled with --disable-net-redirections: "It can produce completely unexpected results. This kind of feature should not be part of a shell but a special tool. And that tool has existed for years already, it's called netcat." To my part, I strongly recommend you to take look on socat. Definitely the best network swiss army knife. Why is it not enabled in Debian ? Because bash in Debian is compiled with –disable-net-redirections:

“It can produce completely unexpected results. This kind of
feature should not be part of a shell but a special tool. And
that tool has existed for years already, it’s called netcat.”

To my part, I strongly recommend you to take look on socat. Definitely the best network swiss army knife.

]]> By: mt http://thesmithfam.org/blog/2006/05/23/bash-socket-programming-with-devtcp-2/comment-page-1/#comment-79440 mt Wed, 03 Jun 2009 12:05:55 +0000 http://thesmithfam.org/blog/?p=21#comment-79440 There's also ncat (part of nmap). Supports proxy. http://nmap.org/ncat/ There’s also ncat (part of nmap). Supports proxy.

http://nmap.org/ncat/

]]> By: dbabits http://thesmithfam.org/blog/2006/05/23/bash-socket-programming-with-devtcp-2/comment-page-1/#comment-65221 dbabits Mon, 24 Nov 2008 21:12:25 +0000 http://thesmithfam.org/blog/?p=21#comment-65221 can anyone show how to do the same if i'm behind a corporate proxy? Somehow i need to specify the proxy's url here can anyone show how to do the same if i’m behind a corporate proxy?
Somehow i need to specify the proxy’s url here

]]> By: David http://thesmithfam.org/blog/2006/05/23/bash-socket-programming-with-devtcp-2/comment-page-1/#comment-57915 David Tue, 16 Sep 2008 01:05:08 +0000 http://thesmithfam.org/blog/?p=21#comment-57915 A tad late, but technically all those "\n" should be "\r\n". The RFC calls for CRLF line termination. A tad late, but technically all those “\n” should be “\r\n”. The RFC calls for CRLF line termination.

]]> By: Connect-back Shell - Defending the Box « Neohapsis Labs http://thesmithfam.org/blog/2006/05/23/bash-socket-programming-with-devtcp-2/comment-page-1/#comment-45853 Connect-back Shell - Defending the Box « Neohapsis Labs Fri, 18 Apr 2008 20:40:10 +0000 http://thesmithfam.org/blog/?p=21#comment-45853 [...] known for quite some time - it’s easily discovered on the blogosphere in articles here and here for example. Since this is built-in to bash by default in most instances, the main method of [...] [...] known for quite some time – it’s easily discovered on the blogosphere in articles here and here for example. Since this is built-in to bash by default in most instances, the main method of [...]

]]> By: Dave http://thesmithfam.org/blog/2006/05/23/bash-socket-programming-with-devtcp-2/comment-page-1/#comment-23223 Dave Sun, 22 Jul 2007 14:26:41 +0000 http://thesmithfam.org/blog/?p=21#comment-23223 I'm afraid I have no idea what you're talking about by "backconnect". Are you talking about the server side? I’m afraid I have no idea what you’re talking about by “backconnect”. Are you talking about the server side?

]]> By: Anonymous http://thesmithfam.org/blog/2006/05/23/bash-socket-programming-with-devtcp-2/comment-page-1/#comment-23212 Anonymous Sun, 22 Jul 2007 08:47:11 +0000 http://thesmithfam.org/blog/?p=21#comment-23212 can you post the backconnect shellcode? can you post the backconnect shellcode?

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