1

Description

This script lets you find out who is on your network.

This could use some tweeks.
I have made some changes too this script but credit goes to Hunter.

Source Code

#!/bin/bash

echo "By 9H4C7K3R2 - v1.0"
echo "@ Script allowing you to scan and detect if a device connects/disconnects from your network"
echo
echo "[+] Starting script (CTRL+C to stop)"
echo "[+] Available interfaces"
ifconfig -a | sed 's/[ \t].*//;/^\(lo\|\)$/d'
echo -n "[+] Which interface do you want to use ? "
read interface
echo -n "[+] Set the time between each scan (default is 10 sec): "
read pause

if [[ $pause == "" ]]
then
    pause=10
    echo "[+] Scan every: $pause secondes"
else
    echo "[+] Scan every: $pause secondes"
fi

range=$(ifconfig $interface | grep -E 'inet addr:' | sed -re 's/inet\ addr\:([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})//g;s/Bcast\://g;s/Mask\:([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})//g' | sed -e 's/255/0\-255/g' | sed -e 's/^[ \a]*//')

if [[ -z ${range} ]]
then
        range=$(ifconfig $interface | grep -E 'inet adr:' | sed -re 's/inet\ adr\:([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})//g;s/Bcast\://g;s/Masque\:([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})//g' | sed -e 's/255/0\-255/g' | sed -e 's/^[ \a]*//')
fi

while [ 1 ];
do
    nmap -sP $range > .host.save
    cat .host.save | sed -e 's/Starting.*//' | sed -e 's/Host.*//' | sed -e 's/Nmap\ done.*//' | sed -e 's/Nmap\ scan\ report\ for\ //' | sed '/^$/d' > .host.save

        echo "[+] Next scan in $pause sec"
        sleep $pause

    nmap -sP $range > .host.bis.save
    cat .host.bis.save | sed -e 's/Starting.*//' | sed -e 's/Host.*//' | sed -e 's/Nmap\ done.*//' | sed -e 's/Nmap\ scan\ report\ for\ //' | sed '/^$/d' > .host.bis.save

    diff .host.save .host.bis.save > .result

    if [ -e .result ];
        then
                if [ ! -s .result ]
                then
                        echo "[+] Nothing Detected"
            rm .host.save .host.bis.save
                else
            echo "[+] Modification Detected"
            cat .result | sed '1d'
            rm .host.save .host.bis.save
                fi
        fi
done