A Denial of Service essentially happens when a hacker/attacker floods a target machine with malicious traffic until the time all its resources are utilised and exhausted resulting in the system going offline. Distributed denial of service is essentially the same, only that it enlists other machines/computers in the attack: the stakes, as they say, are much amplified here. Here’s a list of 8 major DDoS Attacks.
A UDP flood attack is a denial-of-service (DoS) attack using the User Datagram Protocol (UDP), a sessionless/connectionless computer networking protocol. Using UDP for denial-of-service attacks is not as straightforward as with the Transmission Control Protocol (TCP). However, a UDP flood attack can be initiated by sending a large number of UDP packets to random ports on a remote host. As a result, the distant host will: check for the application listening at that port, see that no application listens at that port and reply with an ICMP Destination Unreachable packet.
2.Ping of Death
A ping of death is a type of attack on a computer that involves sending a malformed or otherwise malicious ping to a computer. A correctly formed ping message is typically 56 bytes in size, or 84 bytes when the Internet Protocol (IP) header is considered. Historically, many computer systems could not properly handle a ping packet larger than the maximum IPv4 packet size of 65535bytes. Larger packets could crash the target computer. In early implementations of TCP/IP, this bug was easy to exploit. This exploit affected a wide variety of systems, including Unix, Linux, Mac, Windows, printers, and routers.
3.Reflected / Spoofed attack
A distributed denial of service attack may involve sending forged requests of some type to a very large number of computers that will reply to the requests. Using Internet Protocol address spoofing, the source address is set to that of the targeted victim, which means all the replies will go to (and flood) the target.
A Nuke is an old denial-of-service attack against computer networks consisting of fragmented or otherwise invalid ICMP packets sent to the target, achieved by using a modified ping utility to repeatedly send this corrupt data, thus slowing down the affected computer until it comes to a complete stop.
Slowloris is a piece of software written by Robert “RSnake” Hansen which allows a single machine to take down another machine’s web server with minimal bandwidth and side effects on unrelated services and ports. Slowloris tries to keep many connections to the target web server open and hold them open as long as possible. It accomplishes this by opening connections to the target web server and sending a partial request.
This describes a situation where a website ends up denied, not due to a deliberate attack by a single individual or group of individuals, but simply due to a sudden enormous spike in popularity. This can happen when an extremely popular website posts a prominent link to a second, less well-prepared site, for example, as part of a news story.
7.Zero Day DDoS
General term used to describe vulnerabilities and exploits that are still new and haven’t been patched yet.
A SYN flood is a form of denial-of-service attack in which an attacker sends a succession of SYN requests to a target’s system in an attempt to consume enough server resources to make the system unresponsive to legitimate traffic.