What is DNS Distributed Denial-of-Service? Core Principle and Hazard Analysis

at the moment of high-speed operation of digital services, the stability of network services is directly related to enterprise operations and user experience, and DNS, as the core hub of network address translation, may cause large-scale service paralysis once it encounters malicious attacks. This article will focus on DNS Distributed Denial-of-service, dismantle its core operating principles, analyze the specific means of various attacks, interpret the multiple harms it brings, and share the basic prevention direction to build a complete cognitive system for readers of such cyber threats.

What is the core definition of DNS Distributed Denial-of-service?

to understand DNS Distributed Denial-of-service, it is first necessary to clarify its essential properties and how it differs from ordinary network attacks.

1, the essence of DNS Distributed Denial-of-service

DNS Distributed Denial-of-service is a type of malicious network behavior against the domain name system. Attackers send request traffic far beyond their processing capacity to the target DNS server or associated services through various means, or use protocol vulnerabilities to consume their system resources. Ultimately, the DNS server cannot provide domain name resolution services for legitimate users, which in turn causes the complete paralysis of websites, applications and other network services that rely on the service.

2, the difference with ordinary Distributed Denial-of-service

ordinary Distributed Denial-of-service usually targets business servers directly, while DNS Distributed Denial-of-service targets "address translators" of network services. Once successful, not only will the target business be disrupted, but the entire network ecosystem that relies on the DNS server will have access failures. Moreover, the characteristics of the DNS protocol make it easier to amplify such attacks, and attackers can trigger large-scale invalid requests with small traffic, which is cheaper and more destructive.

The core operating principle of DNS Distributed Denial-of-service

DNS Distributed Denial-of-service can be successfully implemented, the core lies in taking advantage of the design characteristics of the DNS protocol or the limited resources of the system.

1, the principle of DNS Distributed Denial-of-service

the core of this type of DNS Distributed Denial-of-service is to use up the bandwidth and processing resources of the target server with a large number of invalid requests. The attacker will control a large number of puppet hosts, and send domain name resolution requests to the target DNS server to forge the source address. The server will continue to return responses to the non-existent source address, and at the same time process a steady stream of new requests. Eventually, due to full bandwidth, CPU and memory exhaustion, it cannot handle normal requests from legitimate users.

2, Protocol Vulnerability DNS Distributed Denial-of-Service Principle

part of DNS Distributed Denial-of-service exploits the design flaws of the DNS protocol, such as DNS amplification attacks. Attackers will send small requests with forged source Internet Protocol Addresses to open recursive DNS servers. These recursive servers will send a large number of query requests to authoritative DNS servers, and eventually direct several times or even dozens of times the response traffic to the forged target IP, which is the object that the attacker really wants to attack. With the help of resources from third-party servers, the attack effect is amplified, which greatly enhances the destructive power of DNS Distributed Denial-of-service.

Common attack types of DNS Distributed Denial-of-service

depending on the attack method, DNS Distributed Denial-of-service can be divided into many specific types, each type has its own unique implementation path.

1, DNS recursive query flood attack

this is one of the most common types of DNS Distributed Denial-of-service, attackers control the botnet to send a large number of forged recursive query requests to the target recursive DNS server, most of these requests point to non-existent domain names, the server needs to constantly query multiple authoritative servers, a large number of invalid operations will quickly consume the server's CPU, memory and bandwidth resources, in a short time will cause the server to fail to respond to legitimate requests.

2, DNS cache poisoning with Distributed Denial-of-service

attackers in the DNS server cast false cache records at the same time, will send a large number of abnormal requests to interfere with the normal server cache update process, not only to achieve the purpose of tampering domain name resolution results, but also consume server resources, triggering DNS Distributed Denial-of-service effect, this kind of attack both data tampering and service paralysis double threat.

Typical Hazards Caused by DNS Distributed Denial-of-Service

DNS Distributed Denial-of-service is not limited to network service interruption, but also extends to business operations, user trust and other levels, causing chain negative effects.

1, directly lead to the complete paralysis of business services

once the DNS server encounters DNS Distributed Denial-of-service, the user can not convert the domain name to Internet Protocol Address, all relying on the server's website, e-commerce platform, corporate office system will not be able to access normally, for e-commerce enterprises, during the attack of the order loss, transaction interruption will directly cause huge economic losses; for government and enterprise units, it may affect the normal development of government affairs, internal office.

2, causing user trust crisis and brand damage

enterprises that frequently encounter DNS Distributed Denial-of-service will make users question the stability and security of their network services, which will lead to distrust of the brand. Especially in industries with high reliability requirements such as finance and medical care, service interruptions may cause users to panic, lead to customer loss, and brand perception will be irreparably damaged.

sum up, DNS Distributed Denial-of-service is a malicious threat targeting the core hub of the network. From traffic exhaustion to protocol vulnerability exploitation, the attack methods are diverse and destructive, which will not only directly cause business paralysis, but also cause economic losses and brand trust crisis. By understanding its definition, principle and harm, it can help us establish a basic prevention cognition, and build a solid cognitive foundation for the subsequent construction of the protection system and the stability of network services.