Like any other things related to hacking, a DoS Attack isn't always anyone's reach. However, it can be understood very easily if someone explains properly. In today's post, I will try to come up with a brief and simple explanation of the denial of service attacks, before I begin use of confusing phrases like packets and all that. We're going to start at the easiest point.
What Specifically does the denial of service attack do?

We all know that wireless hacking gives us the password for the wireless. Man in the middle attack gives us the power to spy a network traffic. Vulnerability exploitation gives you the control over the victims machine. In all these places where does the DoS stand? What does it exactly do? Basically, what it does is it takes the right of the victim user to use its machine. In today's scenario, it is used to interrupt online services. Many black hats/hacktivists groups do this type of attack on governments and private websites to make them listen to the people's voice (the legitimacy of this method is still a topic of debate, and a lot of hacktivists has suffered jail time for participation in DoS attacks). So generally, it is illegal.
Sponsored Links
Basic Concept

It is a well-known fact a single service can do a work user desires but all the services activated at once can cause some serious damage. Same goes for the websites a web server can handle packets/requests very well but the overload of the packets/requests can cause the website to crash and this id what exactly happens in the DoS Attack.
How DDoS attacks are carried out?

The concept here is very simple like when you visit a website what you do is you send them a request to deliver their content on your web browser in the form of packets. Basically, for DoS attacks it will take more than one packet to carry it out successfully, you need a lot of them. Still, the bandwidth consumed by you while requesting the server to deliver the data is very little. In return the data they send you be huge. This takes their server resources for which they pay a hell lot but they can compensate for it by advertising on their site. So that they can buy a good server which can serve their users efficiently. However, if the number of users suddenly goes up the server gives up and goes down. As soon as the company knows about the attack they just shut their server down so that they would not be wasting any resources on the DoS and the server goes back up as soon as the attack finishes. But nowadays with all kinds of modern tech and new & improved systems a single user can pretend to be a thousand users with a single mouse click. We should know that not only the attackers but the servers are getting smart too with the time and they are becoming more and more efficient in handling this kind of attacks. Now the Distributed Denial Of Service attack comes into existence with the discovery of new and improved servers. It is like you visit a page and start refreshing it very fast say like 1000 times per second so you become equivalent to a thousand users and not only you there are others too which are doing the same thing at the same time so you all become something like million at the same time sending requests causing the server to overload with the packets received and the server goes down. Websites like Google and Facebook have very strong servers and very smart algorithms that prevent them from this puny kind of attacks their websites are smarter they simply block the IP address which seems suspicious. But it's not only the websites that are getting better the black hats out there are improving too searching for other workarounds this leaves huge scope for other attacks to be developed.
Sponsored Links
A live DOS attack on your machine.

1. Kali Machine (May works on any Linux):
we are going to execute a simple command in the terminal which is going to freeze the operating system. Most probably it may work on other Linux distros too but not sure about that.

Warning: This command is going to freeze your system and mostly it does not recover until you force it to restart. And any kind of unsaved work will sure be lost if did not save it. Just copy and paste the command given below and see the freeze.

:(){:|:&};:



What this command exactly does is that it sends a command to the system to keep opening process very fast for an infinite period and after a couple hundreds or thousands of processes depending on your rig it gives up and freeze.
Sponsored Links

2. Windows machine (Using A Batch file)
This one is even simpler that the Linux one and you could actually understand the code by actually looking at it.
What you have to do is:
fire up the notepad
and write codes given below or just copy paste
:1
bash name.bat
goto 1
and save it names.bat
In the above code and the name of the file you can put whatever name you want in place of “name” but the extension “.bat” should remain same.

If you look at the script carefully
you will see that this script does two things.
1 Opens up the another instance of the same script.
2. Goes to the beginning of the script.

So in every execution, the number of processes slowing down your PC will double up.
The attack is of exponential form.