how to use netcat?

I typed:
nc -v -L -e cmd.exe -p 139 -s xxx.xxx.xxx.xxx but i didn't get anything on the next row. What happened with that. Was I blocked by the network policy?

Thx

g00rkha

:D

My best guess is that it is because you tried to bind cmd.exe to port 139 which is already in use by Windows for Netbios...

Try using a different port

I agree, what are your perm's on the system though?

Kelvin://

Well, normally if Netcat can't bind a port it gives an error message like:
Can't bind xxx.xxx.xxx.xxx:139: Port in use or some other similar error.

Personally, I don't think you should be running cmd.exe off of any listening connection anyways... You're obviously just out to setup a backdoor, so I don't see why anyone here should be helping you.

i believe you told netcat to be a server, listen on port 139 and give a command promt when anyone connects. if you don't get a prompt back thats what its doing.

chsh is right, you should be using another port like 443

Does it mean I still can use this port (139) because the service (sorry if i'm not mistaken) give Netcat priority over NETBIOS service which is at a lower priority because it is bound to ANY IP address? Because of I bind I bind "in front of" some services that may be listening on the port.

I tried to use port 443 but it gave me the message that I could not bind with the port. Thanks.

two things..

First, no netcat will not have a higher priority than netbios. When a service is bound to a port, the only way to get rid of it is to kill the process.

Second, If you set up the listener and you get a blank line and your prompt does not return, that probably means the listener is waiting for a connection. To verify this open another window and type

unix: netstat -na |grep <netcat port>
windows: netstat -na |more --> and just look for the port netcat is using.

Make sure that port is in "listening" state

Like I said earlier though...try using a high port that will not conflict with any already in use....something like 23456.

Once the port is listening, open another session and try:

telnet <target.ip> <port #>

Try a higher port.

c:\>nc -d -l -p 6000 -e cmd.exe

X11R6 is already running on port 6000 ...
Look at your local /etc/services !!!

TCP 0.0.0.0:6000 0.0.0.0:0 Listening

Invictus>Does it mean I got a port opened? and then should I telnet using 6000 or the standard port for telnet?

Mr. Dude>What's X11R6?

Mr. Dude do you see the prompt?

Do you have cmd.exe in Linux?

wait a second, what os are you installing nc on?

Tedob1> I am using Windows 2000 Server

Quote:

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Originally posted here by g00rkha
TCP 0.0.0.0:6000 0.0.0.0:0 Listening

Invictus>Does it mean I got a port opened? and then should I telnet using 6000 or the standard port for telnet?

Mr. Dude>What's X11R6?

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Yes...this means port 6000 is open....

Just try doing a telnet to port 6000, not the standard telnet port (23)