What is DNS Spoofing and Cache Poisoning?

In April 2022, hackers targeted the customers of eight Malaysian banks by urging them to download malicious apps. The apps stole user credentials and forwarded the messages to the malware operators. Bad actors love social engineering, and even distribute the spoofed websites via Facebook ads.

This is just one of the cybercrimes reported in 2022, and the list is long. As per Cybercrime Magazine, people lost over $6 trillion to malicious and fraudulent activities in 2021 alone.

Statistics like these make it a must to know about different kinds of spoofing attacks and the ways to prevent them.

However, this piece focuses on what is DNS spoofing and cache poisoning, actions often leading to larger cybersecurity issues. The danger with these is that they’re often not visible to the naked eye of an unsuspecting user. First of all, let’s establish what a Domain Name System (DNS) is.

What is a DNS?

A Domain Name System (DNS) is like a quick access phonebook. If you want to call a friend, you simply do it with the help of the contact details saved on your phone; this way, you don’t have to memorize everyone’s number.

In the same manner, the internet uses a directory called DNS. All computers (including your mobile phones and tablets) are associated with an exclusive number called an IP address linked with a domain name. 

So, whenever you want to visit a website, there’s no need to enter the long IP address—you can just enter the domain name. For example, amazon.com. DNS is what turns the simple domain name into the IP address for devices to understand.

DNS usually contains other information too, including but not limited to SPF and DKIM records.  

What is a DNS Lookup?

In general, DNS lookup refers to checking the DNS record when it returns from the DNS server. This is just like how we check the phonebook to know the caller; it translates the people’s email addresses and domain names into numbers (IP address).


What is DNS Spoofing?

DNS spoofing is a common type of cyberattack in which the hacker uses modified DNS records for steering traffic to a fake website. This is typically done to obtain personal information or trick the target into making payments in the account of the spoofer.

At times, the spoof DNS directs the target to login into a fake account (which they think is real), and ultimately their credentials are stolen to cause harm. In most DNS spoofing cases, the malicious websites install viruses on your device to obtain data for a long time. 


Attack Steps

How does DNS spoofing work? Here’s a quick breakdown:

  • Reconnaissance: Hackers learn everything about the victim’s environment through publicly available DNS data. This exercise isn’t short-term., Instead, it aims at long-term planning for a bigger scam. So, they covertly obtain the information of the target for launching the DNS spoof charge.
  • Access: The attackers misuse free access to find unauthorized entries into the DNS zone. The authoritative name servers make new DNS records as they accept dynamic updates.
  • Attack: The aim is to cause Denial-of-Service (DoS) or Man-in-the-Middle attacks, which intends to flood the server to the point where the system completely shuts down. These indications will help you know how to detect DNS spoofing.


DNS Spoofing vs. DNS Cache Poisoning

The terms DNS spoofing and DNS cache poisoning are used interchangeably; however, there’s a difference between the two. Generally speaking, DNS cache poisoning is one of the ways to initiate a DNS spoofing attack.

There are multiple ways to conduct this cyberattack, such as compromising the DNS server, mounting DNS cache poisoning, man-in-the-middle techniques, guessing the sequence number, etc.

Whereas in the DNS cache poisoning method, the attacker forges a DNS and injects it into the records to obtain, misuse, divert, or modify the incoming and outgoing information.


Why is DNS Spoofing Dangerous?

DNS spoofing possesses great risks, as your DNS contains crucial information about your domain. It can open a massive vulnerability and result in anything from man-in-the-middle attacks to malware infestation. Let’s discuss just a few of the potential issues from DNS cache poisoning

Malware Infection

This is one of the common risks involved in a DNS spoofing attack in which the target is steered to a malicious website with virus-infested downloadable links.

According to EfficientIP’s 2020 Global DNS Threat Report, close to 79% of the surveyed companies became victims of DNS attacks in 2020. On average, each company lost $924,000 to hackers.

Data Loss

Often, attackers that employ DNS spoofing aim to steal data from banks and telecom companies. By doing so, they compromise the personal and professional details of the customers of these organizations.

Hindering Updates

DNS spoofing also hinders the security updates if the spoofed website includes internet service providers. This means your system is unprotected from evolving viruses and phishing attacks.

Government-Based Censorship

At times, the government of a country censors some websites. These bans usually pertain to pornography or political content. Many authoritarian countries have huge lists of censored content, including anything related to women’s rights, politics, religion, and social media sites.

How to Prevent DNS Spoofing?

Now that we’ve discussed what a DNS spoofing attack is, let’s find out the ways to prevent it. 

As many as 4.29 billion people use the internet for various purposes, increasing exposure to spoofers. In this section, we’ll talk about how to prevent DNS spoofing:

Use Detection Tools

Human capacity is limited in viewing DNS requests, so DNS spoofing detection is something to be left to proper tools to scan all the incoming and outgoing data packets.

Use DNS Security Extensions (DNSSEC)

Another feasible way to prevent DNS cache poisoning is by deploying the DNSSEC protocol, which works on a unique cryptographic signature saved along with other DNS records.

Setup End-to-End Encryption

Setting up an end-to-end encryption protocol will disallow the spoofer to make a copy of the unique security certificate belonging to the original website. Read about the ways to recognize email spoofing to understand this better.

Scan Your Devices For Malware

Malware detection software installed helps you get rid of viruses, spyware, and other hidden programs that support cache poisoning. Also, it’s necessary to use a downloaded program as poisoning could spoof the online search results, too.

Don’t Visit Suspicious Sites, Including via URLs

Don’t click links you don’t recognize or feel suspicious about. Links and hyperlinked icons on social media, emails, and text messages are the gateways to DNS cache poisoning; hence, you should manually type the URL in the search bar. 

Use a VPN

A Virtual Private Network (VPN) works as an encrypted tunnel to safeguard your privacy, especially on an unknown network. Browsing using a VPN prevents you from all kinds of spoofing to a great extent. Also, you can get a toll free number that can’t be stolen. If you frequently use public WiFi, this is a must for you.

Flush Your DNS

Flushing the DNS cache prevents a poisoning attack by getting rid of the infected data. Open the Windows ‘Run’ program and type “ipconfig /flushdns; and you’ll be able to prevent yourself from DNS spoofing.


Getting Rid of DNS Cache Poisoning is Difficult

Determining whether DNS responses are fake or genuine is a tricky task. Proper DNS monitoring tools are crucial to catch any abnormalities. Still, you should also employ the preventive measures we shared  to stay safe on the internet.

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