What is DNS cache poisoning attack? Comprehensive analysis of principles and hazards

in the underlying logic of Internet communication, the DNS system is like a navigation map of the online world, responsible for converting easy-to-remember domain names into Internet Protocol Addresses that can be recognized by machines. But this critical system is often the target of network attacks, and DNS cache poisoning attacks are one of the most destructive ones. It can not only tamper with users' network access paths, but also cause a series of risks such as information leakage and property damage. This article will dismantle DNS cache poisoning attacks in an all-round way from definition, principle, harm to defense, to help readers build a complete understanding of such attacks.

What is the core definition of DNS cache poisoning attack?

to understand DNS cache poisoning attacks, we must first clarify its nature and positioning, which is the basis for understanding such attacks.

1, the essence of DNS cache poisoning attack

DNS cache poisoning attack is a man-in-the-middle attack, the core of which is to inject fake domain name resolution records into the cache of the DNS server. When the user requests the resolution service of the domain name, the tampered DNS server will return the wrong Internet Protocol Address, directing the user to the malicious website preset by the attacker instead of the original target site.

2, DNS cache poisoning attack target

targets range from the local DNS cache of personal devices to the public DNS servers of operators and enterprises. When attacking personal devices, only a single user's network access will be affected; when attacking public DNS servers, a large number of users may be misled at the same time, causing a wide range of cyber security issues.

What are the operating principles of DNS cache poisoning attacks?

DNS cache poisoning attack can be successfully implemented, relying on the use of DNS system operating logic, understanding its principle in order to find a defensive breakthrough.

1, using the stateless nature of DNS queries

DNS query uses the stateless UDP protocol. After the server receives the query request, it will not verify the legitimacy of the source of the request. An attacker can pretend to be a domain name authority server and send a false resolution response to the target DNS server. As long as the request ID in the response matches the query ID of the server, it will be stored in the cache. This is the most common implementation method of DNS cache poisoning attacks.

2, with the persistent propagation feature of cache

DNS cache exists to reduce duplicate queries and improve resolution efficiency, cache records will be retained in the server for a period of time. Once the DNS cache poisoning attack successfully injects false records, these error messages will continue to take effect for the valid period of the cache, continuously misleading subsequent user requests until the cache records are automatically cleared or manually updated.

What are the typical hazards of DNS cache poisoning attacks?

DNS cache poisoning attack is highly destructive, and its harm penetrates into multiple levels of user network access, which needs to be paid enough attention.

1, inducing users to visit malicious websites

this is the most direct harm of DNS cache poisoning attacks. Attackers will build phishing pages that are highly similar to target websites. When users are misled into these sites, sensitive data such as account passwords and payment information will be directly obtained by attackers, which will lead to personal information leakage or property damage.

2, implantation of malicious programs and viruses

some malicious websites guided by DNS cache poisoning attacks will automatically implant Trojans, ransomware and other malicious programs into user devices. These programs will steal user privacy data in the background, and even encrypt files in user devices, forcing users to pay a ransom to recover data, causing great trouble and loss to users.

3, disrupt the enterprise's network service availability

if the enterprise's internal DNS server suffered DNS cache poisoning attacks, employees may not be able to access the enterprise's internal systems and business platforms, resulting in a significant decline in office efficiency, and may also affect the enterprise's external services in serious cases, damaging the enterprise's brand perception and business interests.

How to effectively defend against DNS cache poisoning attacks?

for the characteristics and principles of DNS cache poisoning attacks, the industry has formed a relatively complete defense system, from technology to management multi-dimensional construction of protection barriers.

1, the use of secure DNS protocol

the traditional DNS protocol lacks verification mechanism, it is the main breakthrough of DNS cache poisoning attack. The DNSSEC protocol can verify the DNS resolution records through digital signature technology to ensure that the resolution results received by users are true and effective, and prevent the injection of false records from the root cause.

2, regularly clean and update the DNS cache

whether it is a personal device or an Enterprise Services device, you should regularly clean the DNS cache to shorten the valid period of cache records. In this way, even if you encounter a DNS cache poisoning attack, the effective time of false records will be greatly compressed, reducing the continuous harm caused by the attack.

3 Choose a reliable DNS server

individual users should choose the operator's official or well-known public security DNS server, which usually has a complete protection mechanism to effectively resist DNS cache poisoning attacks. Enterprise users can build internal dedicated DNS servers and configure strict access control and authentication rules to improve the security of their own DNS system.

To sum up, DNS cache poisoning attack is a typical network attack against DNS system. By injecting false resolution records to mislead users' access paths, it will cause various hazards such as information leakage and property damage. Its operation principle takes advantage of the stateless characteristics of DNS protocol and the propagation of cache, and the use of security protocols, regular cache cleaning, and selection of reliable servers can effectively reduce the risk of DNS cache poisoning attacks. Only by fully understanding all dimensions of such attacks can we build a protective wall for cyber security.