Distributed Denial Of Service Attacks

LAND DOS attacks: Local Area Network Denial attack is a DoS attack in which a special poison spoofed packet in send to a computer, causing it to lock up itself in a loop.

Denial of service – Denial of service or DOS is an attempt to make a machine or network unavailable to its users. The services that were available to the user wouldn’t be available anymore. Although the result of a DOS attack does not lead to data theft. However a great deal of time and money can cost the company. An example of a service being stopped is email, or can be a loss of network connectivity. There could be no access to shared storage and no one would be able to access the internet while the DOS attack.

The exponential increase use of the Internet to communicate, conduct business transactions, access personal banking, healthcare, education at confront of being anywhere has become an everyday lifestyle for many people around the globe. This reliance on computers, laptops, devices and other Internet of Things to access the Internet means, organizations, businesses and the government have also seen an increase occurrence of sophisticated attacks.

Denial of Service (DoS) attack is a very common cyber menace that renders websites and other online means inaccessible to intended users. There are various types of DoS threats and nearly all directly target the core server structure. Others abuse weaknesses in application and communication proprieties. DoS is also used as a cover-up for other wicked actions, and to take down security applications like web firewalls. A prosperous DoS attack is very obvious and impacts the entire online user base.

These attacks usually put a heavy load on the target by making regular requests very rapidly. It is hard to distinguish if a web server is stormed by thousands of clients, or if there is a DoS attack in progress. A simple way to force the problem of heavy load is to use a server farm together with a load balancer. This will help against small attacks, but not against a DDoS started from several hundred hosts. Furthermore, increasing the number of servers is rather expensive.

Simply put, denial-of-service attacks are attacks meant to prevent users of a cloud service from being able to access their data or their applications. By forcing the victim cloud service to consume inordinate amounts of finite system resources such as processor power, memory, disk space or network bandwidth, the attacker (or attackers, as is the case in distributed denial-of- service (DDoS) attacks) causes an intolerable system slowdown and leaves all of the legitimate service users confused and angry as to why the service isn’t responding.

A denial of service attack on a network could take one of three possible forms (Razmov & Juels, 2000). A malicious party (the attacker) could cause the network not to transmit messages it should be sending in order to offer service to a subset or all of its clients. On the other end of the spectrum, the network could be caused to send messages, which it should not be sending. By far the most common form of DoS in today’s networks is causing excessive bogus traffic (a.k.a. flooding the network) in the direction of a particular server, which in the end will prevent legitimate users from getting the service they could otherwise be receiving from that server.

DDOS is a type of DOS attack where multiple compromised systems -- which are usually infected with a Trojan -- are used to target a single system causing a Denial of Service (DoS) attack. Victims of a DDoS attack consist of both the end targeted system and all systems maliciously used and controlled by the hacker in the distributed attack.

Denial of Service (DOS) or Distributed Denial of Service (DDOS) is one of the biggest security risks in cloud computing as well as any other internet based services. DOS or DDOS generally functions by the attacker sending large amounts of data packets, such as simple TCP/UDP or really any other

Denial-of-service is an attack aimed to refuse access for legitimate users and disrupt service availability according to www.msdn.microsoft.com. This type of security threat according to www.tech.co.uk is rapidly increasing on the Internet due to open doors on Websites. By using the Internet, companies increase the risk of denial of service attack. Denial of service can also be caused by too many connected to a server at the same making run slow or unavailable to others. People who deliberately abuse a network server are often difficult to track down.

A recent increase of application layer Denial of Service attacks (DoS) on the Internet has swiftly shifted the focus of the research community from traditional network-based denial of service. Denial of Service (DoS) and the associated Distributed Denial of Service (DDoS) are simply an attempt by cyber-attackers to exhaust the resources available to a network, application or service so that genuine users cannot gain access. Cyber-attackers find application-layer most vulnerable and are able to device more creative methods of attack, are able to recruit other zombie systems referred to as botnets to amplify their attacks and the apparent difficulty of detecting and mitigating the attacks, all of these with little known solution. Application-layer DoS/DDoS attacks emulate the same request syntax and network level traffic characteristics as those of legitimate clients, thereby making the attacks much harder to be detected and countered. Moreover, such attacks usually target bottleneck resources such as disk bandwidth, database bandwidth, and CPU resources. This paper overviews DoS/DDoS concepts, the various types of denial of service attacks, application layer DoS/DDoS and mitigation techniques to curb the growing trend.

DISTRIBUTED DENIAL OF SERVICE (DDoS) Prachi Shah School of Informatics and Computing Indiana University Bloomington Email: pracshah@indiana.edu Abstract--- Distributed Denial of Service attacks are executed by an attacker that uses numerous zombie machines to launch an attack against the victim system. The purpose is to exhaust the connection bandwidth thereby, making a network resource or a service temporarily or indefinitely unavailable to its intended users. Keywords DoS, DDoS, bandwidth, networks, zombie, botnet 1. INTRODUCTION 1.1 Computer Security and Privacy One of the most challenging and important issues faced in the computer networks domain since a very long time now are network security and privacy issues.

Due to reliance on the Internet to conduct business, DDoS present a concern for Connect Groups networks. Stats show UK is second after the US in DDoS attacks at 10.21%. DDoS attacks are an attempt to make an online unavailable by overwhelming it with traffic from multiple sources. They target a wide industry from banks to news websites, and present a major challenge to make sure people can publish and access important information.

Hence as early we discussed DNS is termed as Domain Name System which is used in converting domain names into IP addresses. It is also globally distributed, scalable, reliable database. In DNS and DNSSEC there are many issues which are difficult to defend. The given data in name servers does not have co-ordination between the data origin to data integrity. So this all will lead to Man in Middle attacks. There are some attacks on DNS which effects the performance of DNS. There are many attacks on DNS like

Denial of Services: The main aim of this attack is to bring down the targeted network and make it to deny the service for