In today’s internet and tech environment, cyber attacks are a constant and growing issue every company and website needs to be prepared for. Without the right precautions and support, attackers can cause real harm to your organization and website. One way attackers can cause that harm is with DNS spoofing or poisoning. To help you figure out how to prevent DNS spoofing, we’ll walk you through what it is, how it works, and what you can do about it.
To fully understand DNS spoofing, it’s important to understand DNS and DNS servers. To start, each computer and server has a unique Internet Protocol (IP) address that’s a number string ID that signals to websites what computer is using the site. These number string IDs are hard for people to remember, so instead, we use domain names to keep track of what website we’re on. The DNS “domain name system” is then what translates the domain name into the right IP address. The DNS servers—resolving name server, root name servers, top-level domain (TLD) name servers, and authoritative name servers—are then what enables the translation or lookup process between domain name and IP addresse
The DNS lookup process works like this:
DNS spoofing or poisoning is a cyber attack that uses the DNS servers to give your web browser the wrong IP address and send you to a fraudulent website instead of the one you wanted to visit. DNS spoofing will mimic legitimate DNS server activity to send users to a malicious website—one that’s usually designed to look like the original site but that will steal confidential information. Whether through altered files or corrupted server data, attackers will send users to the wrong place and utilize that vulnerability. A variation of this kind of attack is DNS cache poisoning. With this attack, your operating system and computer will save the fraudulent IP address in your computer’s cache memory. Then when you attempt to pull up the domain you want, it’ll continue to pull up the malicious website instead.
There are several ways for attackers to perform a DNS spoofing attack, but there are three that are the most common—and therefore the most important to prepare for.
A DNS hijacking is when an attacker uses the DNS servers themselves to send users to malicious websites. The attacker might take over routers, redirect communications, or even use malware on endpoints. Commonly, an attacker will reconfigure the DNS servers so that all user requests through the servers send to the fraudulent IP address.
This kind of attack is where an attacker puts something in between a request for an IP address and the DNS servers. An attacker will intercept a DNS query before it can go through the real DNS servers and instead send back a fraudulent IP address to the computer. With the fraudulent IP address, the web browser then takes the user to the malicious website. Essentially, the DNS query interceptor is a man-in-the-middle that directs users to the wrong website.
The other two attacks could potentially lead to cache poisoning, but there’s an additional way attackers can put the wrong IP address in a computer’s cache memory. Email spam and ad spam can actually be used to embed the incorrect IP address into the computer’s memory. Attackers might send emails with links, and if a user clicks the link, the link will take them to a malicious website and poison their computer cache. Click ads can also be used in a similar way to set up a DNS spoofing cache poisoning attack.
Attackers can use any of the three methods on their own or in tandem to orchestrate a DNS spoofing cyber attack. Attackers will have different motives for their attacks, but most of them will follow a very similar pattern in how they orchestrate their attacks.
Why do attackers use DNS spoofing? What are they trying to do? These are some of the common reasons attackers will want to use this kind of cyber threat—and what risks of DNS spoofing to be aware of:
With these risks from DNS spoofing in mind, it’s time to explore how to prevent DNS spoofing from happening in the first place. Like with all cyber security, there’s no perfect solution that can completely guarantee no attacker will breach your defense. But there are steps you can take to protect your users and drastically reduce the risk of a DNS spoofing or poisoning attack. Here are some ways to reduce the risk of DNS spoofing:
To be prepared against DNS spoofing and poisoning attacks, your solution can encompass several precautions. One of the most important preventative measures to take is to use proper TLS/SSL management support. Venafi is ready to help you protect against DNS spoofing with this proper certificate management. Download our TLS/SSL Machine Identity Management Guide to get started protecting your sites against DNS spoofing and poisoning.