There are several different variations of the DDoS attack but in brief, it is an attack that sends multiple requests to a web server until the server cannot cope with the traffic anymore and the website becomes unavailable.
DDoS attacks have changed and evolved with time and as they become more sophisticated they become more of a challenge to stop and counter whilst still becoming more dangerous. In 2016 the DNS provider Dyn was attacked by a massive botnet to swamp the regional DNS data centers. You can read more about the Dyn attack.
DDoS attack styles
1. Volumetric Attack
A volumetric attack is a style of DDoS attack that is fairly simple in idea. The network level attack aims to sature the targets bandwidth with so many requests that it becomes unavailable. This attack is simplistic, effective and incredibly disruptive to the website and server. In recent years botnets have grown in size and complexity which has allowed people to increase the size and scale of the Volumetric attacks. You can help to negate these attacks through the use of Scalable Protection Schemes which can help to protect against such attacks.
2. SYN Flood
The SYN flood attack takes advantage of the Transmission Control Protocol (TCP). The TCP uses a three-way handshake between the client and the server. When the client requests connection to the server it sends a synchronised (SYN) message to the host server.
3. UDP Flood
By definition, UDF Flood is one kind of DDoS attack which targets host resources with USER DATAGRAM PROTOCOL (UDP) packets. The purpose of this kind of attack to flood random ports of the remote server. This is one of the common ways to harm computer networks. As a result of UDP flooding, the firewall protecting the targeted server can also become drained, resulting in a denial-of-service to legitimate traffic.
4. HTTP Flood
In an HTTP Flood attack, Hackers use Get or Post HTTP requests to take down servers or online services. There is two main modes of HTTP Flood attack: Get & Post. The HTTP Flood attack intends to force the server to distribute as many resources as possible to serve the attack, so that trying to deny genuine users access to the server’s resources.
5. Ping of Death
A death ping is a type of attack on a computer process that integrates delivering a computer malformed or otherwise malicious ping. Ping is a software utility that is used on an IP network to assess a host’s usability. In a ping packet attack, the attackers send a malformed or very large ping packet to the target host how they can crash the system or inject malicious code into the system.
