What is DNS Spoofing?

What Is a DNS Spoofing Attack?

A DNS spoofing attack is when the attacker impersonates a DNS server and sends answers to DNS queries that are different from those sent by the legitimate server.

The attacker can send any answer he wants to the victim’s query, including false IP addresses for hosts or other types of false information. This could be used to direct a user to a website designed to look like another website or give out false information about services on the network.

In a nutshell, an attacker might trick a user into visiting a harmful website without them knowing. DNS spoofing refers to any attempt to alter the DNS records returned to a user and redirect them to a malicious website.

It can be used for a variety of malicious purposes, including:

• Distribution of malware, ransomware, and phishing scams
• Harvesting user information
• Facilitating other types of cybercrime.

How Does DNS Spoofing Work?

The DNS server converts domain names into IP addresses so that people can connect to websites. If a hacker wants to send users to malicious sites, they will first have to change their DNS settings. This can be done by exploiting weaknesses in the system or through brute force attacks where hackers try thousands of different combinations until they find one that works.

Step 1 – Recon

The first step in a successful attack is reconnaissance — finding out as much information about your target. A hacker will study your business model, employee network structure, and security policies to know what kind of information they should ask for and how they can get it.

Step 2 – Access

Once they have gathered enough information about their target, they will attempt to access the system by exploiting vulnerabilities or using brute force methods. Once they have access, they may install malware on the system to allow them to monitor traffic and extract sensitive data. The attacker can send packets claiming to be from legitimate computers, which will make them look like they are coming from somewhere else.

Step 3 – Attack

When the name server receives these packets, it will store them in its cache and use them next time someone queries it for this information. When authorized users try to access an authorized website, they will get redirected to an unauthorized site instead.

DNS Spoofing Methods

There are several ways an attacker can perform it, but they all rely on tricking the user’s computer into using an alternate DNS server. This allows the attacker to hijack requests and send them to whatever website they want.

1. Man-in-the-Middle Attacks

The most common DNS spoofing attack is called a man-in-the-middle (MITM) attack. The attacker intercepts an email communication between two SMTP servers to read all your Internet traffic in this type of attack. The attacker then intercepts your request for a domain name resolution and sends it through their network instead of the actual one. They can respond with any IP address they want — even one that belongs to a phishing site.

2. DNS Cache Poisoning

The attacker uses a botnet or compromised device on their network to send false responses to DNS queries, poisoning the local cache with incorrect information. This can be used for hijacking domain name systems (DNS) and man-in-the-middle attacks.

3. DNS Hijacking

The attacker changes their IP address to appear as though they are the authoritative name server for a domain name. They can then send forged DNS responses to a client requesting information about this domain, directing them toward an IP controlled by the attacker instead of using public DNS servers correctly. This attack is most common against customers who have not implemented security measures on their routers or firewalls.

How To Prevent DNS Spoofing?

Implement DNS Spoofing Detection Mechanisms

DNSSEC is one of the proposed solutions for this issue. DNSSEC is an extension for DNS that provides authentication and integrity for records and provides non-authoritative data from DNS servers. It ensures that responses are not tampered with during transmission. It also provides confidentiality for data traffic between clients and servers, so only those with valid credentials can decrypt it.

Perform Thorough DNS Traffic Filtering

DNS traffic filtering is the process of inspecting all incoming and outgoing traffic on your network. This allows you to block any suspicious activity from occurring on your network. You can do this by using a firewall or other security software that offers this functionality.

Regularly Apply Patches To DNS Servers

Apply security updates to operating systems, applications, and databases regularly.

Use a Virtual Private Network (VPN)

If you don’t have access to an HTTPS connection, then use a VPN. A VPN creates an encrypted tunnel between your computer and the website or service you’re accessing. Because they encrypt traffic in both directions, preventing ISPs from seeing what websites you’re visiting and what data you’re sending or receiving.

Use Firewalls

Install a firewall on every system that connects to the Internet. A firewall will block all incoming connections that have not been explicitly allowed by the network administrator.

Use MTA-STS

You can use MTA-STS to mitigate DNS spoofing. The entries saved in the MTA-STS policy file, downloaded over HTTPS, are compared to your MTA’s MX records queried over DNS. MTAs also cache MTA-STS policy files, making a DNS spoofing attack more difficult to execute.

You can monitor and resolve deliverability issues by enabling TLS-RPT, allowing receivers to send over SMTP TLS reports to your email address. This would help you stay abreast of problems with an unencrypted connection. 

Enable Logging and Monitoring of DNS Queries

Enable logging and monitoring of DNS queries so that you can track any unauthorized changes made to your DNS servers.