In today’s world, where almost everything is done online, cyber threats are becoming more common and more dangerous. Cybercriminals use a variety of techniques to gain access to sensitive data, such as phishing attacks, malware, and ransomware. One such technique that has been making headlines recently is DNS poisoning. DNS poisoning is a type of cyber attack that involves corrupting the domain name system (DNS) in order to redirect users to malicious websites. While this may sound like a tactic used solely by cybercriminals, ethical hackers are also known to use it as a means of testing a system’s security.
How DNS Works #
Before we delve into what DNS poisoning is, let’s first understand how DNS works. DNS is like the phone book of the internet. It translates domain names, such as google.com, into IP addresses, such as 184.108.40.206, which is what computers use to communicate with each other. When you type a website’s domain name into your browser, your computer sends a request to a DNS server to find the IP address associated with that domain name. The DNS server then returns the IP address to your computer, which allows your browser to connect to the website’s server and display the website.
What is DNS Poisoning? #
DNS poisoning, also known as DNS cache poisoning or DNS spoofing, is a type of cyber attack that involves corrupting the DNS cache of a computer or network. The DNS cache is a temporary storage area that stores the IP addresses of recently accessed websites. When a user types a domain name into their browser, the browser checks the DNS cache first to see if it already has the IP address associated with that domain name. If it does, the browser uses the IP address to connect to the website’s server. If it doesn’t, the browser sends a request to a DNS server to find the IP address.
In a DNS poisoning attack, the attacker corrupts the DNS cache of a computer or network by replacing legitimate IP addresses with malicious ones. When a user types a domain name into their browser, the browser checks the corrupted DNS cache and is redirected to a malicious website instead of the legitimate one.
Types of DNS Poisoning Attacks #
There are two main types of DNS poisoning attacks: client-side attacks and server-side attacks.
Client-side attacks involve infecting a user’s computer with malware that modifies the DNS cache. When the user types a domain name into their browser, the malware redirects them to a malicious website instead of the legitimate one.
Server-side attacks involve compromising the DNS server itself. The attacker gains access to the DNS server and modifies the DNS cache to redirect users to malicious websites.
Why Ethical Hackers Use DNS Poisoning #
While DNS poisoning is a dangerous cyber threat, it can also be used for good. Ethical hackers, also known as white hat hackers, use DNS poisoning as a means of testing a system’s security. By performing a DNS poisoning attack, ethical hackers can identify vulnerabilities in a system’s DNS cache and help organisations fix them before cybercriminals can exploit them.
Ethical hackers also use DNS poisoning as a means of gathering intelligence. By redirecting users to a fake website, ethical hackers can observe how users interact with the website and gather valuable information about user behaviour and preferences.
Examples of DNS Poisoning Attacks #
DNS poisoning attacks have been used in some high-profile cyber attacks in the past. One such example is the Kaminsky attack, named after the security researcher who discovered it. The Kaminsky attack exploits a vulnerability in the DNS protocol to corrupt the DNS cache of a computer or network. The attacker then redirects users to a fake website that looks identical to the legitimate one. The fake website can then be used to steal sensitive information, such as usernames and passwords.
Another example is the Iranian Cyber Army’s attack on Twitter in 2009. The attackers compromised Twitter’s DNS server and redirected users to a website that displayed pro-Iranian messages.
How to Protect Yourself from DNS Poisoning #
There are several steps you can take to protect yourself from DNS poisoning attacks. One of the most important steps is to keep your software up to date. Software updates often include security patches that address vulnerabilities that could be exploited by attackers.
You can also use a VPN (virtual private network) to encrypt your internet traffic and protect your online activities from prying eyes. A VPN can also protect you from DNS poisoning attacks by routing your traffic through a secure server that uses its own DNS cache.
Finally, you can use a DNSSEC (DNS Security Extensions) enabled DNS server. DNSSEC adds an extra layer of security to the DNS protocol by digitally signing DNS records. This makes it much more difficult for attackers to corrupt the DNS cache.
Tools for Detecting DNS Poisoning #
There are several tools available that can detect DNS poisoning attacks. One such tool is DNSlytics, which allows you to check the domain name system (DNS) records of a website and detect any anomalies or suspicious activity. Another tool is DNS Checker, which allows you to check the DNS records of a website and verify that they are correct.
DNS poisoning is a dangerous cyber threat that can be used by cybercriminals to steal sensitive information or spread malware. However, it can also be used for good by ethical hackers as a means of testing a system’s security and gathering intelligence. By understanding how DNS poisoning works and taking steps to protect ourselves, we can help safeguard our digital world from this and other cyber threats.