Welcome to my blog

I am a computer engineer. I also have a post graduate degree in Computer And Network Systems Security.
I created this blog to document as well as share any interesting stuff I come across. I will be posting lots of cool stuff on Computer Networking, Hacking, Puzzles and other things.

 

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this is a test post

Difference between a scripting language and a programming language

A programming language needs to be compiled before it can run, like C or C++ but a scripting language like PHP doesn't. PHP is a server side scripting language and it can be run straight from the server's side without any compiling.

Locking the console in Linux

Install vlock by typing apt-get install vlock.
Change to console by pressing Ctrl+Alt+Fx (x=1-6)
Now type vlock -a or vlock -c

Bash scripting- The Basics

What is bash scripting?
Bash scripting is a type of shell scripting in Linux. Other types of shell scripts include csh, tcsh, ksh, zsh etc.

How to use traceroute when traceroute is not working!!!!

Okay, let me try and do a traceroute to my college website this time.

Understanding how Traceroute works using wireshark

When we are connecting to a website, we are going through different hops or routers. Each time we connect to a website, the path taken could be different. So the hop count will also be different. Using Traceroute, we can determine the path traversed. Traceroute uses a very intelligent method for this.

Anonymous FTP

If anonymous FTP is enabled, you can login remotely using username and password as 'anonymous'. Its very rare to find it these days. But its worthwhile to try it if after doing an nmap scan, you find that FTP port 21 is open, especially if the OS used is XP.

Password hashes in Linux

 The passwords are not stored in clear text. Instead a one way hash function is used. That means it is very difficult for an attacker to crack the password even if the hash is obtained.  The hash can be obtained from /etc/shadow. It will look something like this:

Wireshark

Wireshark is a packet analyzer, one of the best and easiest to use. Its got a beautiful GUI that's really user friendly and you can learn a lot of things by just analyzing the packets by using it.
It is available for windows and linux. Like all cool tools, its pre-installed on Backtrack.

NESSUS - Vulnerability Scanner

First thing you should do is a nessus registration. Go to this link and select the home user http://tenable.com/products/nessus/nessus-plugins/obtain-an-activation-code . An email will be sent to you with the activation code. Now download and install both the Nessus Server and Client from their website. Register using the code provided in the mail.

NMAP

Nmap is a great tool for scanning networks, specific ips, finding out which ports are open etc. Its available for Windows and Linux. Its pre installed on Backtrack. Its an awesome tool to have.

Understanding TCP/IP using Wireshark

I feel that it is best to use a packet sniffing tool like wireshark to understand TCP/IP. The following picture shows the layers of TCP/IP and the protocols involved.

Puzzle 10

A spy is trying to send a secret message,I`m trying to decode it,,can you help me?
He sent these messages:
Lado Mado Bado
Nado Sado Mado
Kado Bado Fado
One of these messages(not as in above order) means:Plan excuted successfully.
other message means:Mission dangerously excuted.
and the third message means:Abort mission immediately.
Now....what does "Lado" mean?

Puzzle 9

Barbera's daughter is my daughter's mother. Who am I to Barbera?

Snort

Snort is also a very popular packet sniffer. It does not prevent attacks, but logs the traffic so that we can get information as to what happened.

Tcpdump

Tcpdump is a packet analyzer for linux. It allows the user to intercept and display TCP/IP and other packets being transmitted or received over a network to which the computer is attached.

Some useful commands

ls                       lists the files and directories

ls -a                     lists the hidden files and directories (files can be made hidden by using a . in front of its   name)

netstat -an     lists the open ports

netstat -rn     displays the internal routing table

pwd                current directory location in terminal

last                  displays the last users who logged into the system and the time in which they did so

lsmod              displays the kernel modules loaded

sudo                super user, previlege escalation

apt-get            installation package (eg. apt-get install gedit)

gunzip 'file'    unzipping file    

tar -xvf 'file'   untaring file

man                if you don't know what a program does for eg. nmap, type man nmap, it will give a lot 
                          of info

uname -a       System info 


df -H              Disk usage

vi                   to view a file

nano              easier tool to view a file than vi


cat                 view a file in the current shell itself i.e; without opening another tab


strings           view text data in a dump file (eg. captured by tcpdump with .dmp extension)


lsof                list open files


gedit             probably the most user friendly text editor, install it using apt-get install gedit

chmod          change mode eg. chmod +x filename creates an exe file

grep             search for data inside a file (eg. grep indy filename displays all lines with indy in it)

File Recovery

Suppose you have the dd of the hard disk. You can recover any file you want from it.

fls sda.dd    (sda is just an example)

Puzzle 8:Shiekh's inheritence

An Arab sheikh tells his two sons to race their camels to a distant city to see who will inherit his fortune. The one whose camel is slower wins. After wandering aimlessly for days, the brothers ask a wise man for guidance. Upon receiving the advice, they jump on the camels and race to the city as fast as they can.
What did the wise man say to them?