Knowing how attackers can attack us, let's understand how DNS interception works and what you can do to protect yourself.
DNS hijacking is one type of DNS attack. This attack can be carried out in three ways:
- By installing malware on the victim's PC;
- By seizing control of routers;
- By hacking the DNS connection.
The attackers then change the IP address of the resource corresponding to a specific domain name and redirect the victim to their own site instead of the site they requested, where the user is prompted to enter their credentials or banking information.
How does DNS interception work?
When registering a domain with a domain registrar, you choose one of the available domain names to which your site's IP address will be linked. Let's say you've chosen the domain name BusinessSite.com.
And if attackers can access the DNS record that stores your site's unique IP and replace it with another one, then when entering a domain name, users will be redirected to the hackers' site, and not to your site.
And how to recognize DNS interception?
DNS hijacking has several “symptoms”:
- Slow page loading
- Pop-up ads even where they should not be;
- Pop-ups that convince the user that their PC is infected with malware.
You can also recognize DNS using a couple of simple steps:
- Ping the questionable domain. If the results show that the IP address does not exist, then everything is in order - your DNS was not intercepted.
- Check your router settings through the admin page. If the DNS settings are changed, then you can start sounding the alarm.
- Use the WhoIsMyDNS tool, which will show you the server answering DNS queries for your site. If the displayed DNS is unfamiliar to you, then you should think about it - you could become a victim of hackers.
The Four Horsemen of DNS Hijacking - Understanding the Types of This Attack
You need to know the enemy by sight, so we will briefly cover four forms of DNS hijacking:
- Local DNS interception. In this case, the attacker installs a Trojan on the user's computer and then changes the local DNS settings, redirecting the victim to malicious websites.
- DNS interception with a router. Using vulnerabilities in the firmware or default passwords, an attacker can hack into the router and change its DNS settings.
- Attack type "man in the middle" (MITM). An attacker can use this attack to intercept queries between users and the DNS server in order to redirect victims to malicious sites.
- Changing DNS records on the DNS server. This allows an attacker to redirect DNS queries to malicious websites that the user may not even be able to distinguish from legitimate ones.
How is DNS hijacking different from DNS spoofing and DNS cache poisoning?
Unlike hijacking, spoofing does not intentionally disconnect the victim's site from the network in order to carry out an attack. Instead, the hacker changes the information in the DNS to take the user to a malicious site.
And when poisoning the DNS cache, an attacker exploits a vulnerability in the DNS configuration. If a server does not validate DNS responses to make sure they are from an authoritative source (for example, using DNSSEC), it will cache invalid responses locally and use them to answer queries from other users who have sent the same query.
How to protect yourself from DNS interception?
- Check your router's DNS settings on the admin page regularly. Attackers often take advantage of firmware vulnerabilities and default passwords to cash in on unsuspecting victims.
- Routers are susceptible to attack, and hijackers use this weakness to cash in on unsuspecting victims. Also, don't forget to change your password regularly!
- Use the Registry-Lock status. It protects domains from unwanted changes, transfers, and deletions, thus making it much more difficult for hackers to work.
- Don't forget about antiviruses! Oftentimes, attackers will try to install malware to infiltrate your system and steal the data needed to intercept DNS. A reliable anti-virus solution stops such attempts in the bud.
- Keep your passwords clean! Use strong passwords and remember to update them frequently to make it much harder for hackers to guess.