What is DNS Hijacking?

The Domain Name System (DNS) is a critical component of the internet’s infrastructure. It acts as the internet’s address book, translating human-friendly domain names like www.example.com into machine-friendly IP addresses like 192.168.1.1. This process is essential for accessing websites, sending emails, and performing other internet-based activities. However, like any system, DNS is vulnerable to attacks, one of the most notorious being DNS hijacking. This article will explore what DNS is, how it works, and delve into the concept of DNS hijacking, its implications, and how to protect against it.

What is DNS?

DNS stands for Domain Name System, a hierarchical and decentralized naming system used to identify computers, services, and other resources connected to the internet or a private network. DNS is often compared to a phonebook, where you look up a person’s name to find their phone number. Similarly, when you type a domain name into your browser, DNS servers translate that name into the corresponding IP address, enabling your browser to locate and connect to the correct server.

How DNS Works

1. Domain Name: When you enter a domain name like www.example.com into your web browser, the process begins with your device sending a query to a DNS resolver.
2. DNS Resolver: The DNS resolver, often provided by your Internet Service Provider (ISP), is responsible for querying DNS servers to find the IP address associated with the domain name. If the resolver has the IP address cached, it will return the result immediately.
3. Root Servers: If the IP address is not cached, the resolver contacts a root DNS server. The root server doesn’t know the IP address but directs the resolver to the appropriate top-level domain (TLD) server, such as .com or .org.
4. TLD Servers: The TLD server, in turn, directs the resolver to the authoritative DNS server that holds the IP address for the specific domain.
5. Authoritative DNS Server: Finally, the authoritative DNS server returns the IP address to the resolver, which then passes it back to your device. Your browser can now connect to the website’s server using this IP address.
6. Caching: To speed up future queries, the resolver caches the IP address for a period of time. This reduces the load on DNS servers and speeds up the resolution process for subsequent requests.

What is DNS Hijacking?

DNS hijacking, also known as DNS redirection, is a cyberattack where attackers manipulate DNS queries to redirect users to malicious websites, often without the user’s knowledge. This is typically achieved by compromising DNS servers or altering the DNS configuration on a user’s device.

Types of DNS Hijacking

1. Router DNS Hijacking: Attackers target a user’s home or office router, altering the DNS settings to point to malicious DNS servers. Once the DNS settings are changed, every device connected to that router can be redirected to malicious sites.
2. Man-in-the-Middle Attack: In this scenario, attackers intercept communication between the user and the DNS resolver. They alter the DNS queries in transit, redirecting the user to fraudulent websites.
3. Compromised DNS Servers: Attackers can directly target DNS servers, changing the records to redirect traffic from legitimate domains to malicious IP addresses. This can affect large numbers of users if a popular DNS server is compromised.
4. Local DNS Hijacking: Attackers install malware on a user’s device that modifies the local DNS settings. This malware directs the device to use rogue DNS servers that serve up incorrect or malicious IP addresses.

Consequences of DNS Hijacking

DNS hijacking can have severe consequences, including:

• Phishing Attacks: Users are redirected to fake websites designed to steal sensitive information such as usernames, passwords, and credit card details. These sites often look identical to legitimate ones, making it difficult for users to detect the fraud.
• Malware Distribution: Users can be redirected to sites that automatically download malware onto their devices, leading to further exploitation, such as data theft, ransomware attacks, or the creation of botnets.
• Censorship and Surveillance: DNS hijacking can be used by governments or organizations to censor content or surveil users by redirecting them to approved or monitored websites.
• Denial of Service (DoS): By redirecting users away from legitimate websites, attackers can cause significant disruption to businesses, preventing access to online services and damaging reputation.

How to Protect Against DNS Hijacking

1. Use Secure DNS Providers: Opt for DNS providers that offer security features such as DNSSEC (Domain Name System Security Extensions), which provides authentication to DNS responses, making it more difficult for attackers to tamper with DNS records.
2. Configure Routers Securely: Change the default login credentials on your router to prevent unauthorized access. Regularly update the router’s firmware to protect against known vulnerabilities.
3. Use Encrypted DNS: Employ DNS over HTTPS (DoH) or DNS over TLS (DoT), which encrypt DNS queries, preventing attackers from intercepting and modifying them.
4. Install Security Software: Use reputable security software that can detect and remove malware designed to alter DNS settings on your device.
5. Monitor DNS Settings: Regularly check the DNS settings on your devices and routers to ensure they haven’t been altered without your knowledge.
6. Awareness and Vigilance: Be cautious of phishing emails or suspicious links that could lead to malware installation. Always verify the URL of the websites you visit, especially when entering sensitive information.