DNS pollution is also known as DNS hijacking, which is a means of network attack. By manipulating the response of the DNS server, the domain name accessed by the user is incorrectly resolved to the IP address specified by the attacker. This is often the case with redirected traffic, where attackers can redirect users to fake websites to steal login credentials or other sensitive information. Some countries/organizations also use DNS pollution to block/restrict access to specific websites as a way of content censorship; Then there's the AD push, which redirects users to specific AD pages where attackers can profit from the ads; Spread malware, users who are redirected to malicious websites may download and install malware, such as viruses, trojans, etc.

DNS contamination tampers with the responses of DNS servers, and user queries for specific domain names are mistakenly directed to IP addresses controlled by attackers. When a user attempts to access a website, the device will query the IP address of the website from the DNS server. If the DNS server is contaminated, it will provide the wrong IP address, causing the user to be redirected to the server set by the attacker instead of the website intended to visit. This kind of attack destroys the novelty and openness of the Internet, and infringes the privacy and security of users.

The point of understanding DNS contamination is to recognize how it undermines the normal functioning and trust system of the Internet, without violating user privacy and security, and also undermines the openness and freedom of the Internet.

To prevent DNS contamination, it is recommended to use some measures, such as using secure DNS services and enabling DNS encryption technologies, such as DNS over HTTPS or DNS over TLS, to encrypt DNS queries and prevent tampering. Consider using virtual networks to protect network traffic, such as DNS queries, which are not easily monitored or tampered with by third parties. Check the local DNS Settings to make sure they haven't been tampered with. Keep operating systems and software up to date to fix security vulnerabilities that may be exploited.

The potential impact of DNS pollution on network security is multifaceted, such as data leakage, malware transmission, service interruption, content censorship, trust system destruction, privacy violation, etc. The sensitivity to DNS contamination attacks is higher for the financial services industry, healthcare industry, e-commerce industry, government and public sector, technology industry, telecommunications industry, energy industry, education industry, media and entertainment industry, and law industry, which have strict requirements for cybersecurity and data protection.