Fun Bash (Faith is the evidence of new birth, not the cause of it.)

GNU Bourne Again shell  (Author Stephen Bourne) or Bash is a popular Unix shell that provides us with a very powerful working environment it also provides a scripting engine which allows us in writing simple scripts and automating procedures using exiting Linux tools and commands.  Quick automation of any given task is an essential requirement of any security professional and also it becomes a necessity to survive in such a fast pace life. we can take real-time like scenarios and learn how to use bash to automate the task. Follow along with me by just typing below command in Linux just replace the domain name(website) with your interested one.

It’s time to dive in the sea

#Scenerio 1

Finding all the anywebsite subdomain listed on the index page and find there corresponding IP addresses

wget www.anywebsite.com

more index.html

clear

cat index.html |grep "href="

cat index.html |grep "href=" |cut -d"/" -f3 |more

cat index.html |grep "href=" |cut -d"/" -f3 |grep "anywebsite\.com"|more

#remove extra delimiter

cat index.html |grep "href=" |cut -d"/" -f3 |grep "anywebsite\.com"|cut -d'"' -f1 |more

#remove duplicate with unique option 

cat index.html |grep "href=" |cut -d"/" -f3 |grep "anywebsite\.com"|cut -d'"' -f1 |sort -u

#grep

sort out with grep

grep -o '[A-Za-z0-9_\.-]*\.*anywebsite.com' index.html |sort -u 

grep -o '[A-Za-z0-9_\.-]*\.*anywebsite.com' index.html |sort -u > anywebsite.txt

clear

cat anywebsite.txt

host www.anywebsite.com

#extract ip address

host www.anywebsite.com | grep "has address" |cut -d" " -f4

#write bash file 

clear

vm

nano anywebsite.sh

#!/bin/bash

for url in $(cat anywebsite.txt);do

host $url |grep "has address" |cut -d" " -f4 

done

#save

chmod 755 anywebsite.sh

./anywebsite.sh

#Same exercise with a single line

for url in $(grep -o '[A-Za-z0-9_\.-]*\.*cisco.com' index.html |sort -u); do host $url|grep "has address"|cut -d" " -f4;done

Party isn't over yet. Try out other commands along.

#check vpn interface

ifconf tap0

clear

ping 192.168.31.220

man ping

clear

nano ping-loop.sh

#!/bin/bash (bash subhang)

for ip in $(seq 200 210); do

echo 192.168.31.$ip

done

chmod 755 ping-loop.sh

./ping-loop.sh

------------------

#!/bin/bash (bash subhang)

for ip in $(seq 200 210); do

ping -c 1 192.168.31.$ip

done

./ping-loop.sh

----------------------

#!/bin/bash (bash subhang)

for ip in $(seq 200 210); do

ping -c 1 192.168.31.$ip |grep "bytes from" |cut -d" " -f 4|cut -d":" -f1

done

./ping-loop.sh

---------------------------

>run each command parallel to increase the speed

#!/bin/bash (bash subhang)

for ip in $(seq 200 210); do

ping -c 1 192.168.31.$ip |grep "bytes from" |cut -d" " -f 4|cut -d":" -f1 & 

done

./ping-loop.sh

Finally...  Thank you and be proud of yourself for trying out.