DNS cache poisoning: All You Need To Know In 5 Easy Steps

Ajay Ohri


DNS Cache Poisoning (aka ‘DNS Spoofing’), A cyber-attack that exploits the framework of domain names (DNS) vulnerabilities by diverting Internet traffic away from and towards fake servers. One of the reasons why DNS poisoning is so harmful is that it can spread to the DNS server from the DNS server. A DNS cache is “poisoned” when an incorrect entry is received by the server. To put this into perspective, when a hacker takes control over a DNS server and then alters data in it it can happen.

DNS cache poisoning is known to be this form of attack because the unauthorized IP address resides in the server’s cache. The TTL can also be exploited by attackers so that their fake websites live past the usual cache lifetime of a few hours in the cache. The danger associated with cache poisoning goes beyond the originally infected DNS server. 

DNS cache poisoning allows an attacker to contaminate the data on DNS servers with false information that re-routes your traffic to the attacker’s sites by modifying DNS data, including those controlled by your business and your service provider. Attacks can take many forms once traffic is re-routed, most of which are extremely difficult to detect:

  • An intruder can impersonate your web presence and capture your clients, partners, and employees’ private data.
  • It is possible to trick the anti-spam system into accepting malicious emails and blocking legitimate emails.
  • Web traffic may be sent to a website that looks like the destination you want (say, the website of your bank) but is run By attackers, where you can collect your user name, accounts, and passwords.
  • An intruder will use your website’s “Forgot Password” functionality to retrieve the passwords of your users.
  1. How does caching for DNS work?
  2. How to detect DNS cache poisoning
  3. How to prevent DNS cache poisoning
  4. DNS Cache Poisoning Examples and Consequences
  5. Risks of poisoning by DNS cache

1. How does caching for DNS work?

For a certain amount of time, a DNS resolver can save answers to IP address queries. In this way without having to communicate with the many servers involved in the traditional DNS resolution process, the resolver will respond much faster to future queries. DNS solvers store responses in their cache for as long as they are enabled by the specified time to live (TTL) associated with that IP address.

2. How to detect DNS cache poisoning

How to detect DNS cache poisoning? Track your DNS servers for potential attack signs. Human beings do not have the computer resources to keep up with the number of DNS requests that you will need to log. To distinguish usual DNS activity from attacks, add data security analytics to your DNS monitoring.

A sudden rise in DNS activity on a single domain from a single source suggests a possible birthday attack.

A single-source increase in DNS operation that queries several domain names

Track Active Directory events and suspicious activity activities of the File System in addition to DNS monitoring. And even better, to add important background to your cybersecurity plan, use analytics to compare behavior between all three vectors.

3. How to prevent DNS cache poisoning

DNS cache poisoning prevention, there are many steps that organizations can take. One is that DNS servers should be designed to rely as little as possible on other DNS server trust relationships. Configuring it in this way would make it much harder for an attacker to corrupt a targeted server using their own DNS server.

Another precaution that should be taken is that the DNS server should be set up to allow only the necessary services to run. Getting additional services running on a DNS server that is not needed only increases the size of the attack vector.

Security personnel can also ensure that the most up-to-date DNS version is used. Newer versions of Connect have features that can help avoid cache poisoning attacks, such as cryptographically protected transaction IDs and port randomization.

In preventing these attacks, end-user education is also very relevant. End users should be trained to recognize suspicious sites and if they receive an SSL alert before connecting to a site, do not press the “ignore” button. They should also be regularly trained in the identification of phishing or phishing emails via social media accounts.

Other steps to be taken to avoid cache poisoning attacks are to store only the requested domain-related data and to limit the responses to include only the requested domain-related information.

4. DNS Cache Poisoning Examples and Consequences

DNS has not been planned at all to handle the modern internet. .This incident highlights how reliant we are on DNS. A server is misconfigured by one person, and immediately hundreds of millions of individuals feel the consequences.

For ordinary individuals, DNS cache poisoning attacks are sly and hard to detect. DNS is a trust first device at the moment, which is why it’s quick to take advantage of. Humans trust a DNS fault, and never really check whether the address is the address they were expecting in their browser. Attackers took advantage of this complacency and inattentiveness.

5. Risks of poisoning by DNS cache

The primary risk of DNS poisoning is data stealing. Common targets and easily spoofed are hospitals, financial institution pages, and online retailers, which ensures that any password, credit card, or other personal information can be compromised. Also, the risk of installing a key logger on your computer could cause other sites you visit to be exposed to their usernames and passwords.

Another major danger is that if the website of an internet security company is spoofed, then the device of a user could be exposed to additional threats such as viruses or trojans because there will be no valid security updates.


In summary, Users that visit the compromised domain will subsequently be sent to a new IP address chosen by the hacker.

Poisoning and spoofing of the Domain Name System (DNS) are forms of cyberattack that exploit vulnerabilities of DNS servers to redirect traffic from legitimate servers to false ones. Once you have switched to a fake website, despite being the only one who can, you can be confused about how to solve it. To protect yourself, you would need to know exactly how it works.

The real reason why DNS cache poisoning is such an issue is that there is no real way to verify whether the DNS responses you receive are truly genuine or if they have been manipulated.

So, have you made up your mind to make a career in Cyber Security? Visit our Master Certificate in Cyber Security (Red Team) for further help. It is the first program in offensive technologies in India and allows learners to practice in a real-time simulated ecosystem, that will give you an edge in this competitive world.

Also Read

Related Articles

Please wait while your application is being created.
Request Callback