Domain name hijacking has garnered significant attention in internet security in recent years. Since the Domain Name System (DNS) is crucial for mapping domain names to their corresponding IP addresses, DNS hijacking allows attackers to alter domain name resolution records, causing users to access incorrect servers and potentially stealing sensitive information or exploiting vulnerabilities for other malicious operations. Therefore, effectively addressing DNS hijacking has become a key focus for many network administrators and enterprise security managers.

　　Manifestations of Domain Name Hijacking:

　　First, we need to understand the specific manifestations of DNS hijacking. Generally, it leads to the following situations:

　　Accessing Incorrect IP Addresses: When a user visits a website, the domain name resolution is tampered with, causing the user to access a server controlled by the attacker instead of the original target server. In this case, the user may see phishing websites or download files containing malicious code.

　　Malicious Ad Injection: Attackers, by hijacking DNS resolution, modify the content of the webpage requested by the user, injecting malicious ads, malicious scripts, or other insecure content, thereby affecting user experience and even leading to information leakage.

　　Data Theft and Malicious Redirection: Through DNS hijacking, attackers can capture sensitive user information, including usernames, passwords, credit card information, etc., and then steal it.

　　Why Does DNS Hijacking Occur?

　　DNS hijacking typically occurs in the following scenarios:

　　Security vulnerabilities in DNS servers: Security vulnerabilities in the DNS server itself allow attackers to tamper with DNS records using specific attack methods.

　　Man-in-the-middle attacks: Attackers hijack users' network connections, intercept DNS requests, and tamper with the returned results, causing users to access incorrect addresses.

　　Insecurity of public DNS services: Some public DNS services may lack sufficient security measures, allowing attackers to tamper with resolution records through methods such as DNS cache poisoning.

　　How to Solve the Problem of Domain Name Resolution Hijacking:

　　To effectively solve the problem of domain name resolution hijacking, it is necessary to address it from multiple levels and enhance DNS security.

　　1. Use DNSSEC (DNS Security Extensions)

　　DNSSEC is a security protocol designed for the DNS system to provide data integrity and authentication. When DNSSEC is enabled, the results of DNS resolution are signed, and only legitimate DNS records are received. This way, even if an attacker tampers with a DNS record, the lack of a proper signature prevents verification, and the user's request cannot be altered. Enabling DNSSEC depends on the type of DNS server used. For common DNS servers like BIND, DNSSEC can be enabled in the configuration file. Furthermore, domain registrars and DNS service providers also need to support DNSSEC to ensure the integrity of DNS records.

　　2. Using HTTPS and DNS over HTTPS (DoH)

　　DNS over HTTPS (DoH) is a technology that transmits DNS queries and responses using an encrypted protocol (HTTPS), preventing DNS requests from being eavesdropped on or tampered with. Traditional DNS requests are usually transmitted in plaintext, allowing attackers to steal DNS query records by monitoring network traffic. DoH encrypts DNS requests using the HTTPS protocol, making it impossible for attackers to parse the content even if they intercept the request. To solve the problem of domain name hijacking, clients (such as browsers and operating systems) or DNS service providers can be configured to use the DoH protocol. This not only ensures the privacy and security of DNS requests but also effectively prevents DNS hijacking. 3. Use a Secure DNS Service

　　Using a more secure DNS service is an effective way to prevent DNS hijacking. Many public DNS service providers have adopted more secure transport protocols and enhanced protection against DNS hijacking. These services often also feature encrypted storage of DNS query logs and provide robust anti-hijacking protection. Furthermore, businesses and website administrators can choose to use DNS services with even higher protection levels, which typically offer multiple security features such as DDoS protection, DNSSEC support, and malicious domain blocking.

　　4. Configure Strong Passwords and Multi-Factor Authentication

　　Many DNS hijacking attacks stem from security vulnerabilities in the DNS management account itself. To prevent attackers from tampering with domain name resolution records by stealing the DNS management account, it is recommended to use strong password policies and enable multi-factor authentication (MFA). This way, even if an attacker knows the password, they cannot bypass the additional authentication steps, effectively reducing the risk of domain name resolution being hijacked.

　　5. Regularly Check DNS Records

　　Regularly checking DNS records can help detect potential security issues in a timely manner. Administrators should regularly audit the integrity of DNS records, checking for abnormal resolution records and IP addresses pointing to domain names from unknown sources. Many DNS management platforms also offer change history logging functionality, helping administrators track DNS record changes and promptly detect suspicious operations.

　　6. Preventing DNS Cache Poisoning

　　DNS cache poisoning is a common attack method where attackers inject forged DNS responses into the DNS cache, altering normal domain name resolution results. To prevent DNS cache poisoning, administrators can enable DNS cache clearing mechanisms, regularly clean the DNS cache, and set a short time-to-live (TTL). Furthermore, using DNSSEC can effectively prevent cache poisoning because only legitimate DNS records can be cached.

　　7. Using Firewalls and Intrusion Detection Systems

　　Firewalls and Intrusion Detection Systems (IDS) in enterprise networks can effectively identify and block DNS requests from unknown sources. By monitoring DNS traffic, firewalls can filter requests from suspicious IPs, while intrusion detection systems can analyze anomalies in DNS packets to promptly detect and intercept malicious attacks.

　　Frequently Asked Questions:

　　Q: How to verify if domain name resolution has been hijacked?

　　A: Several tools can be used to verify whether domain name resolution is normal. For example, use the `nslookup` command to query the DNS records of a domain name and compare them with a normal IP address; or visit the domain name and check if the returned website content matches your expectations.

　　Q: Why did my domain name resolution result change?

　　A: Changes in domain name resolution results may be due to an attack or tampering of the DNS server, resulting in altered DNS records. Please check your DNS management permissions and DNSSEC configuration to ensure there are no security vulnerabilities.

　　Q: Do all DNS service providers support DNSSEC?

　　A: Currently, major public DNS service providers, such as Cloudflare, Google, and OpenDNS, support DNSSEC. However, some smaller DNS service providers may not offer this feature, and you need to confirm before using it.

　　Q: Can DNS over HTTPS (DoH) completely prevent DNS hijacking?

　　A: While DoH can encrypt DNS requests and prevent them from being eavesdropped on or tampered with, it cannot completely eliminate all types of DNS attacks. Especially when attackers can control the client or DNS server, the risk of hijacking still exists. Therefore, DoH should be used as part of a multi-layered security approach.

　　In summary, domain name hijacking is a complex security issue, but by taking reasonable preventative measures, such as enabling DNSSEC, using secure DNS services, and regularly checking DNS records, the probability of such problems occurring can be greatly reduced. Protecting the security of domain name resolution is crucial to ensuring normal internet access for users and preventing the leakage of sensitive information.