denial of service attack
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What is a denial of service (DoS) attack?
A denial-of-service (DoS) attack is a cybercrime where an attacker makes an internet site unavailable to legitimate users. This is typically achieved by using multiple computers to flood the target site with repeated requests, overwhelming its capacity and preventing it from responding.
A more advanced form is a distributed denial-of-service (DDoS) attack, where compromised computers, often infected with Trojan horse programs, are triggered to send a barrage of messages to a specific site simultaneously. This can effectively shut down the site, causing significant disruption and financial losses. DDoS attacks are difficult to defend against and can be used for political purposes.
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How does a DoS attack affect a website or computer?
A denial-of-service (DoS) attack disrupts a website or computer by overwhelming it with repeated, automated requests from multiple sources. This flood of traffic prevents the targeted system from responding to legitimate users, effectively making it unavailable. These attacks can cripple e-commerce sites and disrupt essential online services. Distributed DoS (DDoS) attacks, a common variant, utilize compromised computers or devices, often infected with Trojan horse programs, to launch the coordinated assault. Even devices like baby monitors or DVRs can be part of a botnet used in these attacks, highlighting the need for robust security measures.
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What is the difference between a DoS and a DDoS (Distributed Denial of Service) attack?
A denial-of-service (DoS) attack aims to make an internet site unavailable by overwhelming it with requests from a single source, preventing legitimate users from accessing it. In contrast, a distributed denial-of-service (DDoS) attack achieves the same goal but uses multiple compromised computers or devices to flood the target with requests. This distributed nature makes DDoS attacks harder to defend against, as the traffic originates from numerous sources, making it difficult to distinguish malicious requests from legitimate ones.
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What are common signs that a system is experiencing a DoS attack?
A denial-of-service (DoS) attack aims to make an internet site unavailable to legitimate users by overwhelming it with repeated requests from multiple computers. This can prevent the site from responding to genuine traffic.
Common signs of a DoS attack include:
* The system becoming unresponsive or extremely slow.
* Legitimate users being unable to access the service or website.
* A sudden, massive increase in network traffic or requests.These attacks can be orchestrated using compromised computers, often infected with malicious software like Trojan horses, which are triggered remotely. A significant concern is that many software vulnerabilities make it easy for attackers to compromise numerous machines.
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How do attackers carry out a denial of service attack?
Attackers carry out a denial-of-service (DoS) attack by overwhelming an Internet site with repeated requests from multiple computers. This prevents legitimate users from accessing the site.
In a distributed denial-of-service (DDoS) attack, a criminal first infects numerous computers with malicious programs, often disguised as benign files like email attachments. When triggered remotely, these compromised computers simultaneously send a flood of messages to a target site. This overwhelming traffic can effectively shut down the site, making it unavailable. Even devices like baby monitors or digital cameras can be compromised and used in these attacks.
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What measures can be taken to protect against DoS attacks?
To protect against Denial of Service (DoS) attacks, robust security measures are essential. These include implementing vigorous security regimes, which can involve network traffic analysis to identify and block malicious requests. Regularly updating software is also crucial, as unpatched vulnerabilities can be exploited by attackers to compromise systems and launch attacks. Additionally, employing firewalls and intrusion detection systems can help filter out unwanted traffic and alert administrators to suspicious activity. For distributed DoS (DDoS) attacks, which use multiple compromised devices, a multi-layered defense strategy is necessary to mitigate the overwhelming volume of requests.
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denial of service attack (DoS attack), type of cybercrime in which an Internet site is made unavailable, typically by using multiple computers to repeatedly make requests that tie up the site and prevent it from responding to requests from legitimate users.
The first documented DoS-style attack occurred during the week of February 7, 2000, when “mafiaboy,” a 15-year-old Canadian hacker, orchestrated a series of DoS attacks against several e-commerce sites, including Amazon and eBay. These attacks used computers at multiple locations to overwhelm the vendors’ computers and shut down their World Wide Web (WWW) sites to legitimate commercial traffic. The attacks crippled Internet commerce; the U.S. Federal Bureau of Investigation (FBI) estimated that the affected sites suffered $1.7 billion in damages. In its early years the Internet had played a role only in the lives of researchers and academics, but by 2000 it had become essential to the workings of many governments and economies. Cybercrime had moved from being an issue of individual wrongdoing to being a matter of national security.
Distributed DoS (DDoS) attacks are a special kind of hacking. A criminal salts an array of computers with computer programs that can be triggered by an external computer user. These programs are known as Trojan horses since they enter the unknowing users’ computers as something benign, such as a photo or document attached to an e-mail. At a predesignated time, this Trojan horse program begins to send messages to a predetermined site. If enough computers have been compromised, it is likely that the selected site can be tied up so effectively that little if any legitimate traffic can reach it. One important insight offered by these events has been that much software is insecure, making it easy for even an unskilled hacker to compromise a vast number of machines. Although software companies regularly offer patches to fix software vulnerabilities, not all users implement the updates, and their computers remain vulnerable to criminals wanting to launch DoS attacks.
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One of the worst DDoS attacks occurred in October 2016 when a botnet (a network of infected devices) called Mirai brought down the servers of Dyn, an American company that is in charge of much of the Internet’s domain name system (DNS). This attack interrupted much of North American Internet traffic. The Mirai botnet was not made up of infected computers but infected other devices, such as baby monitors, digital video recorders (DVRs), and digital cameras, that could connect to the Internet. Only vigorous security regimes can protect against such an environment.
DDoS and DoS attacks apparently have been used for political purposes, with neighbours of Russia (most notably Estonia in 2007, Georgia in 2008, and Ukraine in 2014 and 2015) having their Web sites targeted in times of conflict in the region. The Russian government has been suspected of being behind these attacks, but its involvement has not been definitively proven.