Denial of Service Attack

A denial of service attack (DoS) is considered to take place only when access to a computer or network resource is intentionally blocked as a result of malicious action taken by another user.

These attacks do not necessarily damage data directly or permanently (although they could), but they intentionally compromise the availability of the resources.

The purpose of a denial of service attack is to render a network inaccessible by generating a type or amount of network traffic that will crash the servers, overwhelm the routers, or otherwise prevent the networks devices from functioning properly. These forms of attacks can include e-mail bomb attacks, sending thousands of e-mails to a particular computer system until that system crash, the software required to carry out denial of service attacks in widely available on the internet.

Another commonly used denial of service attack is the Ping O’ Death. The Ping O’ Death can crash or reboot a computer by sending a ‘ping’ message of greater than 65,536 bytes the default size is 64 bytes. Router updates have nearly eliminated these problems.

Denial of service attacks could be very effective against an Internet based company, since they rely on on-line connectivity. These sorts of attacks could easily disrupt electronic commerce on-line mechanisms.

Meanwhile the distributed denial of service attack (DDoS) is a denial of service attack, in which a multitude of attackers performs denial of service attacks in a coordinated manner to one or more targets. DDoS attacks are a subset of denial of service attacks and there must be more than one source of attacking and also must be coordination between the attackers.
Denial of Service Attack

How does ‘Denial of Service’ attack works?

A denial of service attack is an act of sabotage that attempts to flood a network server or Web server with so many requests for action until it crashes simply cannot handle legitimate requests any longer, causing legitimates users to be denied service.

The attack overwhelms the system’s ability to process web traffic and eventually crashes it.

Denial-of-service attacks can compromise the computers in a network. They can disorganize an organization’s functioning, depending on the nature of the attack.

University security experts were the first to discover the threat of denial of service attacks hiding in the university computer systems. For example, David Dittrich of the University of Washington discovered denial of service program files stored on the university servers’ months before the first widely publicized attacks on E-ecommerce web sites.

Denial of service attacks can be very costly in terms of business lost such as when an e-commerce site is shut down.

The attack, which would typically come from several compromised machine at once, would consumed network bandwidth and use up processing unit cycles on the target machine.

The goal is to stop hosts or networks for communicating in the network or to disrupt network traffic.

The concern would be what is called distributed denial of service attack where take a lot of compromised end systems and flood a server with the intent of making many request or delivering so much traffic to it that it falls off the network.

One of the reasons it takes so long to stop a denial-of-service attack is the hacker sends the bogus traffic using fake IP addresses.
How does ‘Denial of Service’ attack works?