This is How Hackers attacked WikiLeaks, Visa and Paypal

What are DoS and DDoS Attacks?
I can’t tell you who attacked Wiki leaks, PayPal, Visa or any other company out of three quarters companies that faced this brutal Distributed Denial of Service attack (DDoS). But let me tell you they were as easy as putting a cherry on top of a cake. Just Google if you wish to see how brutal they were. WikiLeaks was buried under 10 gb/sec data load on the website, just imagine the intensity of attacks on corporations. To a fact, Anonymous (Hacktivist group) used this in Arab spring.

Who’s behind these attacks?
Individuals tend to consider DDoS destroys by sticking network bandwidth with futile traffic. While that is unquestionably one sort of DDoS attack, others work by eating up server resources. That implies it's workable for a fruitful DDoS assault to be made regardless of the amount of bandwidth you have in light of the fact that it attacks your servers' resources. To truly ensure a network against attacks, both your Internet connection and your servers need guards.

What is DoS (Denial of Service) Attack?
In a denial-of-service (DoS) attack, an attacker endeavours to keep legitimate users from getting to data or services. By focusing on your PC and its network connection, or the PCs and network of the destinations you are attempting to utilize, an attacker might have the capacity to keep you from getting to email, sites, online records, or different services that depend on the affected system.

The most widely recognized and evident kind of DoS attack happens when an attacker "surges" a network with data. When you write a URL for a specific site into your program, you are sending a request to that site's server to see the page. The server can just process a specific number of requests, so if an attacker over-burdens the server with requests, it won’t be able to complete your request. While DDoS is an attack which is performed by various compromised systems that target the same victim. It surges the network with data packets.

Most common types
Smurf: This sort of attack uses large number of Internet Control Message Protocol (ICMP) pings to focus at an Internet Broadcast Address. The answer IP location is ridiculed to that of the expected casualty. Every answer is sent to the casualty rather than the IP utilized for the pings. Since a single Internet Broadcast Address cannot surpass 255 hosts, a smurf attack increases the ping 255 times. The impact of this is slowing the network to a point where it is impossible to use it.

How does it work?
1. The hacker identifies victim’s IP address
2. Hacker recognizes a mediator site that will intensify the attack
3. The hosts on the victim's system reacts to the ICMP requests
4. This makes a lot of movement on the victim's system, bringing about consumption of bandwidth and at last creating the victim's server to crash.

Ping of Death: POD is an old denial of service attack that was successful some time back, but is not even a bit dangerous any more. Ping of Death has additionally been called Teardrop, and a couple of different names.

Inside the IP protocol there are maximum byte allowances for packets (data) sent between two machines. The maximum allowance under IPv4 is 65,535 bytes. At the point when a substantial packet is sent it is isolated over different IP packets. Since the sent information packages are bigger than what the server can deal with, the server can solidify, reboot, or crash.

SYN Flood
SYN is short form for Synchronize. SYN Attack is a kind of Distributed Denial of Service (DDoS) attack that endeavours part of the ordinary TCP three-way handshake to consume resources on the targeted server and render it unresponsive.

Basically, with SYN surge DDoS, the hacker sends TCP connection requests faster than the targeted machine can prepare them, bringing about network immersion.

Security patches for operating systems, router configuration, firewalls and intrusion detection systems can be used to protect against denial of service attacks.