What is Domain Name System (DNS) Spoofing?

DNS spoofing is a kind of more precise method, where the attacker merely modifies the DNS server’s response or blocks it by redirecting the traffic meant for a specific domain to another site controlled by the attacker.

It stated that through controlling the DNS server or the DNS cache, an individual can replace the correct IP address linked to a domain name with an IP address of the attacker’s preference.

The naïve and trusting user, who thinks he or she is accessing a legitimate website, may input personal details, login credentials, or download something dangerous.

How Does DNS Spoofing Work?

The attack begins when a user tries to perform a DNS request for finding the domain name such as www.example.com, into an IP address.

In these types of attacks, instead of the attacker getting a genuine reply for the query that was meant for the DNS server, the attacker secretly tricks the victim into giving a falsified DNS response with an IP address of his or her choice.

This response is cached by the DNS resolver, and therefore, whenever a request is made for the same domain, it will be forwarded to the attacker’s server.

In this attack, the actual response contains an IP address, which is resolved and stored in the cache of the DNS resolver, so the next time the DNS is requested for the domain, the client is redirected to the IP address controlled by the attacker.

 This is because it turns the users to a fake site that looks like the official site of the legal resource.

For instance, if the target is a banking site, the user is likely to be led to a duplicate site that resembles the genuine bank’s site, where, through curiosity, the user inputs dates such as login details or account numbers.

What Are the Potential Consequences of DNS Spoofing?

Data Theft and Phishing

One of the biggest consequences of DNS spoofing is data loss, as attackers are able to redirect users to fake websites that imitate legitimate ones.

They fall prey to fake websites that mimic the look of the real site, and therefore, input personal details such as usernames, passwords, credit card details, and others.

These fake sites are employed in phishing scams whereby the attackers obtain this data for evil use, like embezzlement and acts of identity theft.

Malware Distribution

DNS spoofing can also be used to propagate malware. When a user gets redirected to a malicious website, they may be enticed into installing malicious software like viruses, ransomware, or spyware.

Also Read: What is Malware? How to Prevent Malware Attacks?

Once this malware is installed on the user’s device, it can compromise the device and lead to more threats like security breaches, data loss, or unauthorized access to other sensitive systems.

Business Disruption

DNS spoofing is a great threat to organizations, mainly because it causes a number of disruptions.

There is the possibility for the employee or the customer to be redirected to fake sites, which subsequently leads to account compromise, unauthorized transactions, or loss of customers’ trust.

Also, in the case where an organization’s internal DNS servers are compromised, the productivity of the organization may be affected in the sense that the business may be paralyzed.

Reputation Damage

As stated, the implications of DNS spoofing are far beyond the localized monetary which may be suffered immediately.

As seen in spoofing, if customers or partners get trapped and access the wrong site, which seems to belong to the legitimate business, it will be detrimental to the business. To regain such trust, it can be rather expensive and time-consuming.

Financial Loss

DNS spoofing can lead to a great deal of financial loss, no matter whether it happens to an individual or an organization.

Human losses may include unauthorized transactions or identity theft in case of persons or legal responsibilities, fines, and the expenses incurred to eradicate the harm, as well as to compensate customers in case of companies.

How Does Normal DNS Communication Work?

Normal functioning of the DNS plays an important role in the functioning of the need to access web resources. This process starts when a user enters a domain name that they want to visit, for example, ‘ example.com’ into their browser.

The browser, on the other hand, has to know the IP address of the website in question, which is why DNS is needed. To get the IP address, the browser sends a DNS query to a recursive resolver, most commonly offered by a user’s ISP.

If the resolver has the IP address cached from a previous query, then the resolver immediately returns this address to the browser.

However, if the resolver does not have it cached, then the next process begins, where the resolver starts querying other DNS servers.

Common DNS Spoofing Attack Methods

Man in the Middle (MITM)

Man-in-the-Middle attack occurs when the attacker inserts himself between the user’s device and the DNS server. Another type of DNS Fraud occurs when a user attempts to visit a website; in its stead, their DNS request reaches the attacker.

The attacker has an answer to that request, where they replace the IP address with another, hence directing the user to the wrong site.

The success of an MITM attack usually features the attacker’s ability to infiltrate the network as for example, in the case of unsecured Wi-Fi networks, or utilizing the ARP spoofing technique to channel the traffic.

Once an attacker launches the attack, the only thing he or she can do is to monitor the entire communication process, forward the messages, or even manipulate the data being transmitted or received.

They are especially effective for DNS spoofing, as a victim has no way of knowing that their connection is being hijacked and can easily fall prey to the attack.

DNS Server Compromise

The other type of DNS spoofing attacks is when a DNS server is compromised by the attacker directly. Here, a malicious user intrudes on the DNS server and changes the DNS records resident on the server.

Due to the editing of these records, the attacker can decide how DNS queries will be answered. For instance, they can alter the IP address linked to a hot domain; all the persons who attempt to connect to the mentioned domain will be rerouted to a fraudulent site.

Using this method, an attacker gains a high degree of control over the DNS server, thus amplifying the effectiveness of this technique.

By the time an attack happens, the attacker can manipulate records of multiple domains, thus posing a threat to a number of users.

DNS server compromises are challenging to identify, let alone prevent, if the attacker takes sufficient measures to conceal their actions, and they impact any user who is using the compromised server to perform DNS resolution.

Exploiting Time-To-Live (TTL)

Time-To-Live (TTL) is a value that is placed in the DNS records that determines for how long the DNS response should be cached by Web hosts, DNS Resolvers, or any other intermediaries before the intermediaries are required by them to check the updated record.

The attackers can manipulate TTL in DNS spoofing by putting in fake records with a low TTL value so that the wrong DNS information is used for a short time only, and then the resolver checks again, and another fake response is sent back.

In case of TTL, the attackers utilize spoofed DNS responses containing a high TTL value to flood the DNS resolver with the specified entry, as a result forcing the latter to cache the entry for a long time.

This essentially means that even when an attacker is locked out, they are still able to disrupt clients for several hours or days, depending on the TTL value of the spoofed DNS information.

In both cases, the use of TTL weakens the security and can extend the impacts of a DNS spoofing attack, or make it challenging to trace the attack because of the short time that the entries will exist.

This method is especially risky because, after the initial spoofing has been completed, the attackers can have a lasting impact on the network.

DNS Cache Poisoning Example

The user wants to visit his/her bank’s website using the web address www.bankexample.com. Generally, the DNS resolver requests the DNS server for the IP address of that domain and takes the user to the authentic banking website.

However, in a DNS cache poisoning attack, the attacker taps in between the communication that takes place between the DNS clients and servers.

The attacker is positioned between the resolver and the authoritative DNS server, and breaks the DNS request.

Rather than providing the resolver the proper IP address, the attacker sends the DNS response with an IP address that belongs to him. If the resolver believes this response is authentic, he or she stores the wrong IP address in the cache.

Now, as any other user connected to the same network may do with the source IP address of 192.168.1.2 tries to open “www. bankexample. com”, the DNS resolver provides the poisoned IP address from its cache instead.

This takes the user to a bogus website created by the attacker, and this is a replica of the real banking site. Knowing it is the real banking site, the user submits their credentials to log in to the site.

These particulars are perhaps taken by the attacker, and they can thereafter gain unauthorized access to the user’s bank account.

Preventing DNS Spoofing Attacks

Domain Name System Security Extensions (DNSSEC)

DNSSEC sign secures the additional parts of DNS, which permits DNS responses to be stamped. DNSSEC makes use of two keys- the public and private key by creating a Digital signature for each DNS record.

If a DNS resolver receives a response protected by DNSSEC, then the authenticity and integrity of the data can be checked by comparing the digital signature from the response against the zone’s public key.

This makes sure that the DNS response received has not been manipulated along the way thus warding off DNS spoofing and cache poisoning.

The deployment of DNSSEC calls for working DNS servers as well as resolvers that support DNSSEC, and some proper practices in key management to be followed.

Use Trusted DNS Servers

Another important practice that can help to protect from DNS spoofing is using only the servers that are recognized as reliable.

DNS servers that are reliable are run by organizations that adhere to high security standards to avoid cases like DNS spoofing, among others.

Further, the user and organization should not use an unknown or public DNS that may lack security features.

To eliminate the problem to a great extent, one should configure the network devices to connect to DNS servers offered by reliable providers, including Google Public DNS and Cloudflare DNS, among others.

Cryptographically Secured Communication

DNS spoofing is a real threat and protecting communication channels between client and DNS servers should therefore be a paramount concern.

Techniques like Transport Layer Security (TLS), or DNS over HTTPS (DoH) may be used to enhance the level of security and protect the DNS queries and replies against manipulation by an attacker.

By doing so, organizations are able to encrypt their DNS queries and responses, and therefore, their DNS traffic cannot be interfered with by attackers.

Regular System Updates

Maintaining the update of software and systems is one of the basic measures that are followed in cybersecurity to prevent DNS spoofing attacks. Security patches and updates are gray with vulnerabilities in DNS software, operating systems, and network devices.

Failure to apply such updates can lead to vulnerability and make the systems susceptible to DNS spoofing attacks by attackers.

It is recommended that organizations adopt a patch management policy that will involve the frequent updating of all patch products for every software, firmware, and operating system in the infrastructure.

Network Security Measures

Measures should be put in place to enhance network security as a way of minimizing DNS spoofing attacks.

This would involve setting up firewalls specifically to prevent unauthorized access to DNS servers, performing constant audits for any form of irregularity in network traffic, and deploying IDS/IDP to alert of any possible attack.

Network segmentation may also limit the attack surface by physically separating the DNS servers from the rest of the network.

Moreover, it is important for organizations to properly configure DNS servers by uninstalling unnecessary services and preventing access to servers only by experienced IT personnel.

IPSec (Internet Protocol Security)

IPSec is a set of protocols that is used for implementing cryptographic security during data communication over a network based on the Internet Protocol.

Through its ability to encrypt and authenticate IP packets, IPSec is able to shield DNS data from modification as it moves through the network.

When IPSec is used together with DNSSEC, it increases the security of the DNS traffic as both the data content and the channel used are secure.

This is because IPSec can be configured to offer end-to-end protection to DNS clients and servers, hence minimizing the chances of attackers engaging in DNS spoofing attacks.

Conclusion

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