DNS security is crucial, as it directly impacts the digital asset security of every user and enterprise. Learning about DNS hijacking can help you better prevent and improve network security. Today, we've compiled a more in-depth explanation of the dangers and mechanisms of DNS hijacking!

The basic principle of DNS hijacking is that an attacker impersonates a domain name server (DNS) and sets the query IP address to one controlled by the attacker. When a user attempts to access a specific website, the request is redirected to the fake site, potentially unaware of the anomaly. This attack can be carried out through various means: local network hijacking, router hijacking, man-in-the-middle attacks, or directly compromising the DNS service provider.

For individual users, DNS hijacking can lead to private data leaks and malware infections. Attackers can forge bank websites or social media platforms to trick users into entering their account passwords. For businesses, the consequences are even more severe: theft of trade secrets, compromised customer data, website outages, and damage to brand reputation. Furthermore, hijacking can be used for large-scale surveillance or online censorship.

DNS hijacking differs from DNS poisoning. Poisoning typically involves large-scale manipulation of DNS query results, while hijacking involves more targeted attacks against specific targets or networks. Both pose a threat to network security, but their protection strategies differ.

Individual users can take the following practical measures to prevent DNS hijacking: Using a trusted public DNS service is the first step. Replacing the system's default DNS server with a well-known public DNS service and enabling encrypted DNS protocols can effectively prevent queries from being eavesdropped or tampered with. Most modern browsers support DNS over HTTPS (DoH) and DNS over TLS (DoT), and users can enable this feature in their settings. Some tools, such as Clash, allow users to specify the use of encrypted DNS through configuration files.

Keep your operating system, browser, and router firmware updated to patch known security vulnerabilities. Install reliable antivirus software and conduct regular scans to detect and remove malware that may modify DNS settings.

Enterprises need a more comprehensive DNS hijacking protection solution: Deploying DNSSEC is a core technology for preventing DNS hijacking. DNSSEC verifies the authenticity of DNS query responses through digital signatures, preventing resolution results from being tampered with. Enterprises should deploy DNSSEC on their domains and encourage the use of recursive resolvers that support DNSSEC validation. The most direct and effective approach is to consult a DNS.com service for professional assistance!

Implementing network monitoring can help detect anomalies promptly. By monitoring DNS query patterns, enterprises can detect possible hijacking attempts. Professional security teams should regularly audit DNS configurations for unauthorized changes.

Using an enterprise-grade DNS firewall can effectively filter out malicious responses. Such solutions can detect and block suspicious DNS activity in real time. Furthermore, strengthening network infrastructure security, including access controls and firmware updates for devices like routers and switches, can prevent attackers from infiltrating the internal network.

Developing an emergency response plan ensures rapid recovery in the event of a DNS security incident. This plan should include how to quickly switch DNS service providers, notify users and customers, and track the source of the attack.

Encrypted DNS is an effective defense against hijacking. Here are some configuration methods: For DoH configuration, users can enable this feature in DoH-supported browsers, such as Firefox. In enterprise environments, DoH settings can be deployed uniformly through Group Policy. DoT configuration is another option for mobile devices or system-level configurations. Users can enable DoT by modifying network settings or using dedicated applications. Professional tools such as Simple DNSCrypt can simplify the deployment of encrypted DNS. These tools often offer user-friendly interfaces, making them easy for non-technical users. Note that some network environments may restrict or block encrypted DNS traffic. In such cases, a service can be an alternative, as it not only encrypts DNS queries but also hides the user's true IP address.

If you suspect DNS hijacking, take the following steps immediately: Clearing the DNS cache is the first step. In Windows, use the "ipconfig /flushdns" command; in macOS, use the following command to remove potentially corrupted DNS resolution records:

sudo killall -HUP mDNSResponder

Check and repair network settings. Review your router, local network settings, and hosts file to ensure they haven't been maliciously modified. Resetting the router to factory settings and reconfiguring it may be necessary. Verify domain name resolution results. Use multiple DNS query tools to compare resolution results, or use third-party online services to verify that specific domain names are resolving correctly. Abnormal resolution results may indicate DNS hijacking. It's crucial for businesses to initiate an emergency response plan, including switching DNS services, notifying relevant parties, and conducting security forensics. Additionally, update security certificates and passwords to prevent credentials from being compromised during an attack.

DNS hijacking is a serious cyber threat, but with proper technical measures and security awareness, individuals and businesses can significantly reduce the risk. Cybersecurity is an ongoing process, and remaining vigilant and updating protective measures are essential to effectively combat the increasingly complex DNS threats.