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Line 1: − + + + − '''DDoS''' is the acronym for '''Distributed Denial of Service.''' The [[SEI|Software Engineering Institute]]- [[CERT]] at [[Carnegie Mellon University]] explained that the telephone system, computer system and the Domain Name System ([[DNS]]) sometimes become unusable during peak hours because of supply and demand. However, when an intruder or hacker interrupts the system, takes control of the computer and prevents the legitimate user to use it and forces the computer to send large amount of email to someone else which can not be handled by the recipient's disk that saves e-mails, a '''Denial of Service (DoS) attack''' happens. If an intruder attacks a particular computer, takes control of it and sends extraordinary amount of data to a website and distribute it to numerous email addresses affecting the users computer network, the intrusion is called '''Distributed Denial Of Service attack'''.<ref>[http://www.cert.org/homeusers/ddos.html What is a Distributed Denial of Service (DDoS) Attack and What Can I Do About It?]</ref>]+ + − + − According to the CERT report, "Trends in Denial Service Attack Technology" the frequent targets of intruders are Windows end-users and Internet Routing Technology. Intruders primary intention in conducting DoS attack is to prevent the use of computer or network resources.+ − ==Reasons Why Internet is Vulnerable to Attacks==+ − Internet connected systems are still vulnerable to DoS attacks despite active security efforts is because of the following reasons:<ref>[http://www.cert.org/homeusers/ddos.html Trends in Denial Service Attack Technology]</ref>+ − * Internet is composed of limited and consumable resources+ − * Internet security is highly interdependent+ + − ==Packet Flooding Attack==+ − '''Packet Flooding Attack''' is the most common type of Denial of Service Attack.The modus operandi of intruders is sending more than acceptable number of packets to a particular destination which consumes the entire bandwidth resources. There are several types of packets used by Packet Flooding Attack tools including: − * '''[[TCP]] Floods'''- SYN, ACK and RST flags are sent to the victim's [[IP]] Address − * '''[[ICMP]] echo request reply (Ping Floods)'''- A stream of ICMP is sent to the victim's IP Address − * '''[[UDP]] Floods'''- A stream of UDP is sent to the victim's IP Address − These attack tools changes the characteristics of packets in the packet stream such as the '''Source IP Address''' to hide the real source of the packet stream. The method of sending packet streams to one or more intermediate sites to create responses that will be sent to a victim is called '''IP Spoofing.'''<ref>[http://www.iss.net/security_center/advice/Underground/Hacking/Methods/Technical/Spoofing/default.htm Spoofing]</ref> Other packet stream attribute being altered by intruders are the '''Source/Destination Ports''' and '''Other IP Header Values'''.+ − + − {{reflist}}+ + + + + + + + + + + + + + + + + + + + + + + − + − − − __NOTOC__
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'''Distributed Denial of Service Attacks''', or '''DDoS Attacks''', effectively flood websites or servers with traffic from many different sources in order to "make the site unavailable."<ref name="attack map">[http://www.digitalattackmap.com/understanding-ddos/ What is a DDoS Attack?], Digital Attack Map</ref> DDoS is a type of [[DoS Attacks|Denial of Service Attack (DoS Attack)]] that uses multiple sources in order to blocks users from accessing the site. It is important to remember that not all service errors are the result of attack behaviors and can occur if a website is overwhelmed by non-malicious traffic as well.<ref>[http://www.us-cert.gov/ncas/tips/ST04-015 Security Tip (ST04-015): Understanding Denial-of-Service Attacks] (February 6, 2013), United States Department of Homeland Security</ref>
==Public Perception==
The public perception of DDoS attacks is negative. It is inconvenient to users who cannot reach their destination, and it can create major problems for the website's registrant, whether it is the website of an individual or an organization. DDoS attacks can become criminal when the attacker asks for money to stop the current attack or to prevent further attacks.<ref name="blog"/> DDoS attacks can also be used by "hacktivists" for political gain, to interrupt free speech, or in protest of perceived injustice.<ref name="attack map"/><ref name="blog"/>
==Outcome==
The outcome of a DDoS attack is that the attacked website is unavailable or runs very slowly. The damage done by these attacks can lead to minor inconveniences, losses in consumer confidence, or large revenue losses.
==Frequent Targets of Intruder Attacks==
==Historical Use==
*DDoS attacks have been used to take down or interrupt the traffic of large sites, making them inaccessible.<ref name=Weiss>[http://www.esecurityplanet.com/network-security/how-to-prevent-dos-attacks.html How to Prevent DoS Attacks] by Aaron Weiss (July 2, 2012), eSecurity Planet</ref><ref>[http://blog.icann.org/2013/04/do-more-to-prevent-dns-ddos-attacks/ Do More to Prevent DNS DDoS Attacks] by Dave Piscitello (April 3, 2013), Internet Corporation for Assigned Names and Numbers (ICANN)</ref> These planned attacks can be committed for political, social, and/or illegal purposes.<ref name="blog"/> Unlike regular DoS attacks, DDoS attacks use multiple computers to attack their victims which often makes the attack harder to stop.<ref name=Weiss/> [[Botnet Attacks|Botnets]], or networks of computers controlled by hackers, are often used in DDoS attacks.<ref>[http://www.prolexic.com/knowledge-center-what-is-ddos-denial-of-service.html What is DDoS denial of service? What everyone needs to know about DDoS], Prolexic</ref>
*Four types of DDoS attacks include:<ref name="attack map"/>
#TCP Connection Attacks: attempting "to use up all the available connections to infrastructure devices"<ref name="attack map"/>
#Volumetric Attacks: attempting to use large amounts of bandwidth
#Fragmentation Attacks: sending so many TCP or UDP fragments that the target cannot assemble them, which slows the system
#Application Attacks: trying to flood one aspect or application on a given site
*A DDoS attack can be bought or traded as a service. For example, an attack that lasts a week can be purchased for $150,<ref name="attack map"/> while an attack that lasts 1 hour can be bought for $30-70.<ref>[http://www.trendmicro.com/cloud-content/us/pdfs/security-intelligence/white-papers/wp-russian-underground-101.pdf Russian Underground 101] (PDF) by Max Goncharov, TrendMicro.com</ref>
*In addition to causing service errors, DDoS attacks can also be used to commit "other cybercrimes, including data breaches or financial fraud."<ref>[https://www.networkworld.com/newsletters/techexec/2013/101113bestpractices.html?page=2 Best practices to mitigate DDoS attacks] by Linda Musthaler (January 10, 2013), Network World</ref>
==References==
==ICANN Policy==
*ICANN does not have a policy that specifically addresses DDoS attacks; however, ICANN's blog has addressed the issue of how to respond to and report a DDoS attack.<ref name="blog">[http://blog.icann.org/2013/04/how-to-report-a-ddos-attack/ How to Report a DDoS Attack] by Dave Piscitello (April 25, 2013), Internet Corporation for Assigned Names and Numbers (ICANN).</ref> If a site is under attack, the 2013 post suggests that the registrant contacts the hosting provider and internet service provider (ISP).<ref name="blog"/> If the attack was proceeded by a threat or a sum of money was demanded to stop the attack, the registrant should contact law enforcement.<ref name="blog"/>
*ICANN's Security and Stability Advisory Committee ([[SSAC]]) also released an advisory in 2006 on DDoS attacks in relation to the DNS.<ref>[http://www.icann.org/en/groups/ssac/dns-ddos-advisory-31mar06-en.pdf SSAC Advisory SAC008: DNS Distributed Denial of Service (DDoS) Attacks] (PDF), ICANN Security and Stability Advisory Committee (SSAC)</ref>
*ICANN's [[SSAC]] released another advisory in 2014 on DDoS attacks and how they may exploit certain security issues in the DNS.<ref name="s">[http://www.icann.org/en/groups/ssac/documents/sac-065-en.pdf SSAC Advisory on DDoS Attacks Leveraging DNS Infrastructure] (PDF), ICANN Security and Stability Advisory Committee (SSAC)</ref> For example, an attacker may use a victim's spoofed IP address to make multiple queries to an open recursive DNS server; the server will then respond by flooding the victim's computer with the unsolicited responses.<ref name="sing">[http://singapore49.icann.org/en/schedule/thu-ssac SSAC's Update Presentation at ICANN 49] (PDF and audio)</ref> DDoS attacks that utilize "DNS reflection and amplification" can have "attack data bit rates reportedly exceeding 300 gigabits per second."<ref name="sing"/> The advisory suggests that "ICANN should...facilitate an Internet-wide community effort to reduce the number of open resolvers and networks that allow network spoofing."<ref name="s"/> Additionally, rate limiting and blocking abusive queries may help reduce DDoS attacks.<ref name="sing"/> The SSAC also recommends that DNS software and systems be updated regularly to reduce DDoS vulnerability.<ref name="sing"/>
**Read the [http://www.icann.org/en/groups/ssac/documents/sac-065-en.pdf SSAC's Advisory on DDoS Attacks Leveraging DNS Infrastructure]
**View the [http://singapore49.icann.org/en/schedule/thu-ssac SSAC's Presentation at ICANN 49]
==Legislation==
*[[Computer Fraud and Abuse Act]] (CFAA): this act, last amended in 2008,<ref>[http://en.wikipedia.org/wiki/Computer_Fraud_and_Abuse_Act Computer Fraud and Abuse Act] at Wikipedia</ref> prohibits the unauthorized use of another person's computer, among other things.<ref>[https://ilt.eff.org/index.php/Computer_Fraud_and_Abuse_Act_%28CFAA%29 Computer Fraud and Abuse Act (CFAA)] at Internet Law Treatise</ref><ref>[http://us.practicallaw.com/2-508-3428 Computer Fraud and Abuse Act (CFAA)] at Practical Law, Thomson Reuters</ref> In relation to DDoS attacks, if the hacker used a botnet to perpetrate the attack, he or she could be charged under CFAA in addition to facing civil suits.<ref>[http://us.practicallaw.com/7-516-9293 Distributed Denial-of-Service (DDoS) Attack] at Practical Law, Thomson Reuters</ref> DDoS attackers can also face jail time.<ref name="naked">[http://nakedsecurity.sophos.com/2010/12/09/are-ddos-distributed-denial-of-service-attacks-against-the-law/ Are DDoS (distributed denial-of-service) attacks against the law?] by Graham Cluley (December 9, 2010), Naked Security, Sophos</ref>
**Read more about the [https://ilt.eff.org/index.php/Computer_Fraud_and_Abuse_Act_%28CFAA%29 CFAA].
*Other nations, such as the UK and Sweden, also have anti-DDoS legislature.<ref name="naked"/>
==DNS Award==
Awardees take a proactive approach to preventing DDoS attacks.
==Additional Resources==
*Review facts and watch a video explaining [http://www.digitalattackmap.com/understanding-ddos/ DDoS Attacks]
*View a [http://www.digitalattackmap.com/#anim=1&color=0&country=ALL&time=16097&view=map DDoS Attack Map]
*Read the [http://www.icann.org/en/groups/ssac/dns-ddos-advisory-31mar06-en.pdf SSAC's DDoS Advisory]
*See [http://www.us-cert.gov/ncas/tips/ST04-015 CERT's Security Tips Page] for signs that indicate you may be experiencing a DDoS attack
*View a [http://www.circleid.com/posts/20140318_what_does_a_ddos_attack_look_like/ Visualization of a DDOS Attack]
*Listen to the [http://singapore49.icann.org/en/schedule/thu-ssac SSAC's Presentation at ICANN Singapore] that addresses DDoS attacks and recommendations
==Related Articles==
*[[Botnet Attacks]]
*[[DoS Attack]]
==References==
<references/>
[[Category: Bad Practice]]
[[Category:Glossary]]