What are DNS Attacks and its Types: All you Need to Know

Understanding the potential consequences and the importance of safeguarding against DNS Attacks is crucial for individuals, businesses, and organisations alike. Additionally, the Domain Name System (DNS) serves as the internet's address book, translating human-readable domain names into IP addresses.   

However, this critical infrastructure is vulnerable to a range of malicious activities, from DNS spoofing to DNS tunnelling. A DNS Attack is any attack that targets the dependability or availability of a network's DNS service. Further, read this blog to learn more about DNS Attacks types. 

Table of Contents 

1) Understanding What is DNS 

2) Exploring the types of DNS Attacks 

      a) DoS attack 

      b) DDoS attack 

      c) DNS amplification attack 

      d) DNS hijacking 

      e) DNS tunnelling 

3) Real-world examples of DNS Attacks

4) Conclusion 

Understanding What is DNS 

DNS is a fundamental technology that serves as the backbone of the internet. It is essentially a decentralised directory system that translates human-readable domain names, such as www.example.com, into numerical (Internet Protocol (IP) addresses, like 192.168.1.1, which computers use to identify and communicate with each other across the global network.  

The DNS can be thought of as the internet's address book. When you type a website's domain name into your browser's address bar, your computer queries a DNS server to resolve that domain name into an IP address. This allows your device to locate the web server hosting the requested content, enabling you to access websites, send emails, or engage in any online activity.  

Furthermore, a DNS operates as a hierarchical and distributed system, consisting of various levels of DNS servers, with the root servers at the top. These servers work together to resolve domain names to IP addresses efficiently, and this process typically takes milliseconds, making internet navigation seamless for users. 



 

Exploring the Types of DNS Attacks 

Here is a list describing the different Types of DNS Attacks as follows: 

DoS Attack 

A Denial-of-Service (DoS) attack is a malicious attempt to obstruct the usual functioning of a computer system, network, or online service by overwhelming it with an excessive volume of traffic or exploiting vulnerabilities. Here are eight key points to understand about DoS attacks: 

a) Intent to disrupt: DoS attacks are typically carried out with the intent to disrupt the target's services, making them unavailable to users, customers, or employees. 

b) Traffic overload: Attackers flood the target with a massive volume of traffic, such as network requests, data packets, or connection attempts. This flood of traffic can consume the target's resources and bandwidth. 

c) Resource exhaustion: The aim is to exhaust the target's resources, including CPU, memory, network bandwidth, or disk space, rendering the system incapable of responding to legitimate requests. 

d) Varieties of DoS Attacks: There are various types of DoS attacks, including TCP/IP-based attacks like SYN flood, UDP flood, ICMP flood, and application layer attacks that target specific software vulnerabilities. 

e) DDoS Attacks: Distributed Denial-of-Service (DDoS) attacks involve multiple compromised devices, often forming a botnet, to coordinate and amplify the attack's impact, making it harder to mitigate. 

f) Impact: The impact of a successful DoS attack can vary, ranging from temporary service disruptions to severe financial losses, tarnished reputation, and potential legal consequences. 

g) Motivation: Attackers may have different motivations, including revenge, competitive advantage, hacktivism, or simply causing chaos for the thrill of it. 

h) Prevention and mitigation: Organisations can defend against DoS attacks by implementing key security measures such as firewalls, intrusion detection systems, traffic filtering, load balancing, and Content Delivery Networks (CDNs). Effective incident response plans and monitoring are also crucial for early detection and mitigation. 

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DDoS attack 

The Distributed Denial of Service (DDoS) attack is a maligned attempt to disrupt the normal functioning of a computer network, system, or service by overwhelming it with an orchestrated flood of traffic from multiple compromised devices. Here are six key points to understand about DDoS attacks: 

a) Distributed nature: DDoS attacks are executed from a network of numerous geographically distributed devices, often forming a botnet. These devices, which can include compromised computers, IoT devices, or servers, are controlled by the attacker to send traffic simultaneously. 

b) Volume of traffic: A DDoS attack is intended to flood the target with a deluge of traffic, causing it to become slow, unresponsive, or completely unavailable. This traffic can be in the form of data packets, requests, or connection attempts. 

c) Motivation: DDoS attacks can have various motivations, including financial gain, competition sabotage, hacktivism, or simply causing disruption and chaos. 

d) Types of DDoS Attacks: There are several types of DDoS attacks, including: 

1) Volumetric attacks: Overwhelm network bandwidth 

2) Protocol attacks: Exploit vulnerabilities in network protocols 

3) Application layer attacks: Target specific applications or services 

e) Detection and mitigation: Detecting and mitigating DDoS attacks require advanced security measures such as traffic analysis, rate limiting, traffic filtering, and the use of specialised DDoS mitigation services and hardware. 

f) Impact: DDoS attacks can have severe consequences, including downtime, loss of revenue, damage to reputation, and increased operational costs. They can disrupt online services, making them unavailable to users and customers, leading to significant financial and operational damage. 

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DNS amplification attack 

A DNS amplification attack is a form of DDoS attack that leverages vulnerabilities in the DNS to overwhelm a target with a massive volume of traffic. Here are six key points to understand about DNS amplification attacks: 

a) Exploitation of DNS servers: Attackers exploit misconfigured or open DNS servers that respond to DNS queries from anyone, known as open resolvers. These servers inadvertently become unwitting accomplices in the attack. 

b) Traffic amplification: The attacker sends a small DNS query to the open resolvers, typically with a spoofed source IP address that appears to be the target's IP. The open resolvers, in response, generate a much larger DNS response, amplifying the volume of traffic directed toward the victim. 

c) Massive traffic flood: The amplified DNS responses can be tens or even hundreds of times larger than the original query, causing a flood of data to inundate the target's network and overwhelm its resources. 

d) DDoS Attack objective: The goal of a DNS amplification attack is to exhaust the target's bandwidth, CPU, and memory resources, rendering its services unavailable to legitimate users. 

e) Botnets and coordination: Attackers often control botnets of compromised devices to coordinate and execute DNS amplification attacks on a massive scale, making mitigation more challenging. 

f) Prevention and mitigation: To defend against DNS amplification attacks, organizations can implement measures like rate limiting on their DNS servers, using DNS filtering, disabling open resolvers, and employing dedicated DDoS mitigation services to identify and block malicious traffic patterns. 

DNS hijacking 

DNS hijacking, also known as DNS redirection or DNS poisoning, is a malicious attack where an attacker gains unauthorised control over a domain's DNS settings. Here are six key points to understand about DNS hijacking: 

a) Manipulating DNS records: Attackers alter the DNS records of a legitimate domain, such as changing the IP address associated with a domain name and redirecting traffic to malicious servers under their control. 

b) Traffic diversion: The primary objective of DNS hijacking is to divert legitimate user traffic away from the intended destination to malicious servers. This allows attackers to intercept sensitive data, inject malware, or conduct phishing attacks. 

c) Motives: Attackers may hijack DNS for various motives, including financial gain, espionage, identity theft, or ideological reasons. 

d) Methods: DNS hijacking can occur through several methods, including compromising domain registrar accounts, exploiting vulnerabilities in DNS servers, or manipulating DNS responses. 

e) Mitigation: Protecting against DNS hijacking involves implementing strong authentication and access controls for domain registrar accounts, monitoring DNS records for unauthorised changes, and using Domain Name System Security Extensions (DNSSEC) to sign DNS records to prevent tampering cryptographically. 

f) Real-world impact: DNS hijacking incidents have disrupted organizations, led to data breaches, and even compromised critical infrastructure, highlighting the significance of safeguarding DNS settings to ensure the integrity of online services and data. 

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DNS tunnelling 

DNS tunnelling is a covert data exfiltration technique that exploits the DNS protocol to bypass network security measures. Here are six key points to understand about DNS tunnelling: 

a) Concealed data transfer: DNS tunnelling allows malicious actors to hide data within DNS queries and responses, using the legitimate DNS infrastructure for covert communication. 

b) Use of subdomains: Attackers create subdomains with long, encoded, or encrypted names that serve as a means to transmit data in small chunks. These subdomains often appear as seemingly harmless requests. 

c) Evading security: DNS tunnelling is difficult to detect because DNS is typically allowed through firewalls, and DNS traffic is common in most networks. This makes it an attractive method for bypassing security measures. 

d) Payload types: Attackers can use DNS tunnels to transmit a variety of payloads, including malware, stolen data, or command-and-control communications with compromised devices. 

e) Detection and prevention: Detecting DNS tunnelling requires sophisticated security solutions that analyse DNS traffic patterns, subdomain naming conventions, and the volume of DNS requests. Implementing DNS filtering, traffic monitoring, and threat intelligence can help in preventing such attacks. 

f) Risk and impact: DNS tunnelling poses a significant security risk, as it allows attackers to maintain a persistent presence within a compromised network, exfiltrate sensitive data, and control infected devices without being easily detected. Organisations must be vigilant in monitoring and securing their DNS traffic to mitigate this threat. 

Real-world DNS Attack examples

The following are the real-world examples of DNS Attacks:

1) DNS spoofing: In 2008, Dan Kaminsky, a security researcher, discovered a serious defect in the DNS protocol that allowed attackers to poison the remote DNS servers. This can lead to the theft of sensitive information or distribution of malware. This type of attack, also known as Kaminsky attack.

2) DNS amplification: In 2018, GitHub experienced huge DDoS attack that led to DNS amplification. The attackers were able to briefly take down GitHub by overloading its servers with traffic, spoofing an IP address and sending requests to DNS servers that are vulnerable to violence.

3) DNS tunnelling: Security tools had trouble identifying the malicious behaviour since the DNS Messenger malware communicated with its command-and-control site through DNS tunnelling. This method perfectly captures the insincerity of DNS tunnelling in terms of data theft.

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Conclusion 

Being safeguarded against a DNS attack is vital and can be made possible by understanding the intricacies of DNS attacks. The implementation of robust security measures is essential to protect against the ever-present threat of DNS attacks, ensuring the integrity and availability of online services and data. 

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