penetration programming

Modify the .sh script so that it also works interactively. Specifically, if no hostname is given on the command line, the program should interactively ask for a hostname, starting port, and ending port with three separate prompts, and carry out its scan using those values. After scanning finishes, the program should loop to receive another set of values, stopping only when the user enters a blank host name.

If this feature is implemented properly, it will also allow you to run the script in batch mode, by piping in a plain text file with the hostname on the first line, start port on the second, stop port on the third, and repeating for as many hosts as you wish to scan.

For example, if a file named hosts_to_scan.txt contains a list of hosts and ports in the proper format, the program should now work as follows:

cat hosts_to_scan.txt | ./portscanner.sh

The timeout argument should still work in this case as well:

cat hosts_to_scan.txt | ./portscanner.sh -t 3

.sh

#!/bin/bash #Basic bash port scanner

# CHECKING CONDITION FOR -t OPTION if [ "$1" == '-t' ]; then # IF -t IS USED time=$2 host=$3 startport=$4 stopport=$5 else # IF -t IS NOT USED time=2 host=$1 startport=$2 stopport=$3 fi

function pingcheck { pingresult=$(ping -c 1 $host | grep bytes | wc -l) if [ "$pingresult" -gt 1 ]; then echo else echo "$host is down, quitting" exit fi }

function portcheck { # IF TIMEOUT VALUE OF LESS THAN 1 if [ "$time" -lt 1 ] then echo "Timeout value must be greater than 0, quitting" exit # IF TIMEOUT VALUE IF NOT EQUAL TO 2 elif [ "$time" -ne 2 ] then echo "Note: Timeout changed to $time."

fi

for ((counter=$startport; counter<=$stopport; counter++)) do if timeout $time bash -c "echo >/dev/tcp/$host/$counter" then echo "$counter open" else echo "$counter closed" fi done }

#first, check that the host is alive pingcheck # next, loop through the ports portcheck

hosts_to_scan.txt (note: not sure if this is correct)

www.yahoo.com 75 85 www.google.com 78 84 www.bing.com 77 87