shellscriptsguide

Start using my Nmap Parser for Port Scanning around

noreply@blogger.com (armageddonsaviour) — Fri, 17 Jul 2009 06:19:46 PDT

Nmap Port Scanning tool is recommended for all system / network admins.

To gather information about conflicting machines all around.

Start using NMAP Port Scanner and use my NMAP Parser shell script to interpret results and/or import to some Database etc ...

Run
nmap -v -O -sT -oG resultgreppable1.txt -oN resultnormal1.txt -oX resultxml1.txt 10.16.2.2-254 10.16.4.2-254 10.16.6.2-254

This Command Scans 3 IP Address Ranges:
And logs results in 3 parsable formats.

We use greppable format.

Next,
Save this Shell Script as "parsenmap.sh"
to interpret results from greppable log file.
#!/bin/sh
#!parsenmap.sh
cat resultgreppable1.txt | grep -i -v "status: Down" | grep -iv "nmap" | grep -v ';' | tr '[()]' ':' | while read line
do
echo $line | awk -F':' '{print $5}' | tr ',' '\n' | while read openport
do
echo "`echo $line | awk -F':' '{print $2,$3}'` `echo $openport | awk -F'/' '{print $1,$3,$5}'` `echo $line | awk -F':' '{print $9}'`"
done
done

chmod ugo+x parsenmap.sh

Run
./parsenmap.sh

It should show you results of Machines with Open Ports.

How to forward X Client Session Output to remote X Server Computer

noreply@blogger.com (armageddonsaviour) — Thu, 18 Jun 2009 19:39:58 PDT

Presenting the howto in a simplified easy to try method ...

Assuming, X Server (denoted by) :0 (Zero) are running on atleast 2 machines say, sunlx1_1 and sunlx1_11.
And you are logged into both the systems (maybe different Username + Password ...).

Assuming, The two computers are connected over LAN.
We will execute / Run Normal Linux Programs / Applications on sunlx1_1 and see the Graphics on another machine sunlx1_11.

We will attempt to do two things:
Start our own XServer on target machine,
Use its XServer to run our XClients ...
(Forward our XClients to target machine's XServer running on Target machine's one of the free virtual consoles switchable using Crtl+Alt+F1 to Ctrl+Alt+F12

You can start many XServers on target machine.
In Linux, Virtual Consoles: F1-F6 are Command Line based.

F7 - associated with default Runlevel 5 Login Screen ...

You can use F9,F10,F11,F12 (4+ easily switchable Graphical Virtual Consoles (one X Server running & providing graphical console on each)

F8 - automatically gets associated with :1 XServer, not available.

And you cannot start an XServer from a graphical virtual console, on which an
XServer is already running

On Target Machine, sunlx1_11,

Switch to a free virtual Console, by pressing say Ctrl+Alt+F1 (use any free virtual console from F1 - F6)

Login (even non-root users can do this) and Run

startx -- :2 &

Wait for sometime ...

Note: Ctrl+Alt+F7 is default :0 screen
You might get your new login screen on say Ctrl+Alt+F9

Allow New XServer to allow connections from other hosts ...
Run,

xhosts +
(Accepts from all hosts (not very secure, but okay to try out ..., but dont forget to disable it (written later in this article)))
or,
xhosts + sunlx1_1
(Accepts only from sunlx1_1)

Run any one of the above command ...

Target machine is now set ...

Move to sunlx1_1
To make this machine forward X Connections to Target sunlx1_11 machine,

You first set its DISPLAY environment variable, that X Applications use ...
Run

echo $SHELL

Note the Shell you are running & appropriately, run any of the following ...
If you are running CSH
Run
setenv DISPLAY sunlx1_11:2

If you are running SH
Run
DISPLAY=sunlx1_11:2
export DISPLAY

Now even this machine is ready ...

Now test X Forwarding ...

Run

xterm &
or
xterm -display sunlx1_11:2 &

Try running sample test script:

On sunlx1_1,

We are creating a sample test script, whose output will appear on sunlx1_11 machine.

Save file as: loader.sh on sunlx1_1

#!/bin/sh
DISPLAY=`head -1 remotexscreen.txt`
export DISPLAY
host="`hostname`"
xterm -T "`echo I am From First Computer: $host`" -e "`date ; sleep 10`"

Set Permissions as follows:
chmod 700 loader.sh

Run on sunlx1_1 as:

sh loader.sh

Now a Graphical Command Window (xterm) should appear on sunlx1_11 for 10 seconds, displaying sunlx1_1's system date, time on sunlx1_11.
(On :2 Virtual Console)

Try Switching through Virtual Consoles, to get the right one ...

You should see, sunlx1_1's xterm prompt (X-Client Application) running on
Target Machine's one of the XServers.

Now how to restore things back to normal?

Reset sunlx1_1's DISPLAY variable to value :0

On sunlx1_1, Run

echo $SHELL

For CSH

Run
setenv DISPLAY :0

For SH
Run
DISPLAY=:0
export DISPLAY

And on Target Machine sunlx1_11,
First Stop Accepting forwarded X Connections ...
Second Shutdown the second X Server we started
Third Logout from the Virtual Shell (Command Line Interface) login Prompt as well.

Open a terminal Window, in the virtual console / XServer (:2) which you want to shutdown.
Run

xhost -
or
xhost - sunlx1_1

Now to Stop / Shutdown / Kill this Graphical Screen,
Press Ctrl + Alt + BackSpace.

If this works well, you will return back to the virtual console with Text Mode Login, from where you had issued command: startx -- :2 &

If this doesnt work,
You will have to start switching among all Text Mode Virtual Consoles.
Ctrl+Alt+F1 - Ctrl+Alt+F6

And find the one from where, you had issued command: startx -- :2 &

Issue the Following Command on Command Shell Prompt:
To Kill/Stop/Shutdown Graphical Screen/X Server

ps -elf | grep :2 | awk -F' ' '{print $4}' | xargs kill -9

dont forget to logout from any other virtual console

Switch back to the free virtual Console, by pressing say Ctrl+Alt+F1 (use any free virtual console from F1 - F6), remember the last time, you had issued the
startx -- :2 &
command from ...
Just find that one (virtual console) ...

Now to logout,
Press Ctrl+D
or
Run
exit

Note: There are other ways to achieve this as well (using XAuth) ...

Implement Tunnel using Shell Scripts

noreply@blogger.com (armageddonsaviour) — Thu, 03 Sep 2009 16:50:27 PDT

To make your PC work like a Port forwarding tunnel,
sh starttunnel.sh (enter)
To Stop Tunnel
sh stoptunnel.sh (enter)

Make Sure you have executed
chmod 700 *.sh
before execution of scripts.

File 1). starttunnel.sh

#!/bin.sh
#Bash Shell Script to make a PC work as Tunnel
#You will need to get Process ID for starttunnel.sh
#using ps -aux | grep starttunnel.sh
#And issue kill -9 (above PID)
#Pressing Ctrl+C/Ctrl+Z wont Terminate/Suspend the Shell Script.
#Only Current Pipe would be broken.
#New Processes would be created again.

#However, it allows only single connection at a time
#not multiple connections

mkfifo response #Make Pipe File
while [ 1 ];
do
echo "Started Pipes"
nc -l -p 3128 < response | nc localhost 3128 > response #Tunnel Command
#sleep 5 #Allow Some time for PipeFile to be actually Deleted ...
if [ -a "response" ]
then
echo "Restarting Pipes ... (Some Connection, could be Denied)"
else
echo "Terminated ..."
exit
fi
done

File 2). stopscript.sh

#!/bin/sh
#Terminates Open Pipes acting as Tunnel
#Kills starttunnel.sh script running in infinite loop.
#On which Ctrl+C, Ctrl+Z Dont Work Well
#Removes Temporary Pipe File Created ...

rm -f response
ps -eaf | grep -w "./starttunnel.sh" | awk -F' ' '{print $2}' | xargs -t kill -9 &
ps -eaf | grep -w "nc" | awk -F' ' '{print $2}' | xargs -t kill -9 &

Change Browser Proxy Settings to make use of this machine's IP Address and Port
This Machine acts as a man in the middle to forwarder to real proxy server.

You can modify this to make your machine a Chat Server on Terminal Window like xterm etc.
Or even, a Transparent Proxy, dumping traffic in a file.