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What is a Man-in-the-Middle (MitM) attack?

Read our blog to find out what Man in the Middle (MitM) attacks are, why they’re dangerous and how to identify, recover from and prevent them.

man in the middle attack

In the fast-evolving world of cybersecurity, man-in-the-middle (MitM) attacks remain a persistent threat, as insidious as they are prevalent. And understanding them is the first step towards defending against them.

In this blog, we’ll be covering:

  • What is a man-in-the-middle attack?
  • How do man-in-the-middle attacks work?
  • Different types of man-in-the-middle attacks
  • MitM attack techniques
  • How common are MitM attacks?
  • Why are man-in-the-middle attacks dangerous?
  • Real-life examples of man-in-the-middle attacks
  • How to identify a man-in-the-middle attack
  • What to do is you’re subjected to a man-in-the-middle attack
  • How to prevent and protect against man-in-the-middle attacks
  • Conclusion

What is a man-in-the-middle attack?

A man-in-the-middle attack is a type of cyber attack where an unauthorized person intercepts communication between two parties. The attacker then secretly relays, and possibly alters, the communication between the two parties, who believe they are directly communicating with each other.

How do man-in-the-middle attacks work?

The core of a MitM attack is interception and decryption. The attacker positions themselves between the communicating parties, intercepting all information being sent. This could be anything from login credentials to credit card numbers. If the data is encrypted, the attacker will attempt to decrypt it, gaining access to the sensitive information.

Different types of man-in-the-middle attacks

Understanding the different types of MitM attacks can help you better recognize and defend against them. So let’s look at some of the most common types of man-in-the-middle attacks.

Internet protocol spoofing

This is a technique where an attacker sends IP packets from a false source address in order to disguise themselves. By altering the address information in an IP packet, attackers can make it appear as though the packet came from a trusted source, thus gaining unauthorized access to a device or network.

DNS spoofing

Also known as DNS cache poisoning, this attack involves an attacker redirecting queries to a different domain by corrupting a DNS server’s cache. This can lead to users being directed to malicious websites instead of the ones they intended to visit.

mDNS spoofing

Similar to DNS spoofing, mDNS (Multicast DNS) spoofing involves an attacker impersonating a device on a local network. This can allow the attacker to redirect local traffic to a malicious device or site.

HTTP spoofing

In this attack, the bad actor intercepts and alters HTTP requests or responses. This can be used to redirect users to malicious websites or to inject malicious content into legitimate web pages.

ARP spoofing

Address Resolution Protocol (ARP) spoofing involves an attacker sending falsified ARP messages over a local network. This can allow the attacker to link their MAC address with the IP address of a legitimate device on the network, effectively ‘hijacking’ the device’s identity.

Secure sockets layer hijacking

SSL hijacking involves an attacker intercepting encrypted SSL traffic between a user and a server. The attacker can then decrypt and read the traffic, potentially gaining access to sensitive information.

Email hijacking

This involves an attacker gaining access to a user’s email account, either through phishing, malware, or other means. Once in control of the account, the attacker can send emails posing as the user, potentially tricking recipients into divulging sensitive information or downloading malware.

Wifi eavesdropping

In this type of eavesdropping attack, an attacker intercepts wifi traffic between a user and a network. This can be done using various methods, including setting up a malicious wifi network that mimics a legitimate one.

Rogue access point

This involves an attacker setting up a malicious wifi network that mimics a legitimate one. Users who connect to the rogue access point can have their traffic intercepted and potentially altered by the attacker.

MitM attack techniques

The following techniques form the backbone of MitM attacks, enabling bad actors to intercept, alter, and even control the communication between two parties. 


Attackers monitor and capture data as it travels over a network. This technique is often used to capture sensitive information, such as usernames and passwords, credit card numbers, and other sensitive information.

Packet injection

In this technique, attackers introduce additional data or code into network traffic. This can disrupt a network, redirect users to malicious websites, or execute other attacks.

Session hijacking

Session hijacking is when attackers take over a user’s session after they’ve authenticated. This allows the attacker to impersonate the user and perform actions on their behalf.

SSL stripping

Attackers downgrade a secure HTTPS connection to a less secure HTTP connection. This allows them to intercept and read the user’s traffic, potentially gaining access to sensitive information.

How common are MitM attacks?

MitM attacks are unfortunately quite common. Their prevalence is due to the numerous attack vectors available and the valuable information that can be obtained. They are a favored technique of many cybercriminals due to their effectiveness and potential for significant damage.

Why are man-in-the-middle attacks dangerous?

Man-in-the-middle attacks pose a significant threat due to their ability to intercept and potentially alter communication between two parties. This can lead to a variety of damaging outcomes, from data theft to service disruption.

The danger lies not only in the immediate impact of the attack but also in the potential long-term consequences for organizations. Let’s look at some of the reasons why MitM attacks are considered so dangerous.

Data theft

Sensitive data, such as passwords and credit card numbers, can fall into the wrong hands during a MitM attack. This stolen information can then be used to commit fraud, identity theft, and other crimes.

Malware injection

During a MitM attack, malicious code can be inserted into legitimate traffic. This code can then be used to steal data, install malware, or disrupt operations.

Denial-of-service (DoS) attacks

MitM attacks can serve as a launchpad for denial-of-service attacks. These attacks can make it difficult or impossible for legitimate users to access a website or service.

Reputational damage

If customers or partners believe that their data is not secure, they may be less likely to do business with the organization. This can lead to significant reputational damage and loss of business.

Real-life examples of man-in-the-middle attacks

MitM attacks have been used against a wide range of targets, from large corporations to individual users. Here are two real-life examples that have caused significant harm to businesses and their customers.


In 2017, there was a confirmed data breach at Equifax that exposed over 143 million Americans. As a result, Equifax created a website called to let customers see whether the breach impacted them. 

The issue was that the website used a shared SSL for hosting – with thousands of other websites using the same certificate. DNS (through fake websites) and SSL spoofing took place to redirect users to a phony website or intercept data from the site. A further 2.5 million customers were then impacted, putting the total at 145.5m.


A 2014 incident occurred when Lenovo distributed computers with Superfish Visual Search adware. This made it possible to create and deploy ads on encrypted web pages and alter SSL certificates to add their own – so attackers could view web activity and login data while someone was browsing on Chrome or Internet Explorer. 

Security software vendors like Microsoft and McAfee coordinated directly with Lenovo to make software updates just after a few days of discovering the vulnerability to remove Superfish adware.

How to identify a man-in-the-middle attack

As they are designed to be stealthy and unnoticeable, recognizing a man-in-the-middle attack while it’s happening can be challenging. However, there are certain signs and symptoms that can indicate a potential MitM attack.

By being aware of these indicators, you can take immediate action to protect your data and systems. 

Slow or unreliable connections

If your internet connection suddenly becomes slow or unreliable, it could be a sign that an attacker is intercepting your traffic. This can be especially suspicious if the slowdown occurs on a network that is usually fast and reliable.

Unexpected errors

If you’re seeing unexpected errors, such as ‘certificate errors’ or ‘page not found’, it could be a sign of an MitM attack. These errors can occur when an attacker is trying to redirect your traffic or interfere with your connection.

Unusual traffic patterns

If you notice a lot of traffic to a website that you don’t normally visit, it could be a sign of an MitM attack. An attacker could be using your connection to send traffic to other websites or to download malicious files.

Change in security settings

If you’ve noticed any changes in your security settings, such as a new certificate being installed, it could be a sign of an MitM attack. An attacker may be trying to install a malicious certificate on your device in order to intercept your traffic.

What to do is you’re subjected to a man-in-the-middle attack

Disconnect from the network immediately

If you suspect that you’re under attack, the first thing you should do is disconnect from the network. This will prevent the attacker from intercepting any more of your traffic.

Change your passwords

If an attacker has intercepted your traffic, they may have gained access to your usernames and passwords. Changing your passwords can help protect your accounts.

Scan your computer for malware

The attacker may have used malware to facilitate the MitM attack. Scanning your computer with a reputable antivirus or anti-malware program can help identify and remove any potential threats.

Report the attack to the authorities

If you believe that you’ve been the victim of an MitM attack, you should report it to the relevant authorities. They may be able to help track down the attacker and prevent them from harming others.

How to prevent and protect against man-in-the-middle attacks

Stronger password protection

Using strong, unique passwords for each of your accounts can make it harder for an attacker to gain access to your information.

Use WPA2-E and EAP-TLS

WPA2-E is a Wi-Fi security protocol designed for enterprise networks, and EAP-TLS is an authentication protocol used within such networks to establish secure connections between clients and servers. Together, they provide a strong security framework for ensuring secure and authenticated access to Wi-Fi networks in large organizations.

Secure connections

Whenever possible, use secure methods of communication, such as HTTPS and SSL/TLS, to protect your data in transit.

Avoid phishing

Be wary of unsolicited emails, messages, or websites that ask for your personal information. These could be phishing attempts designed to trick you into divulging your information.

VPN encryption

Using a virtual private network (VPN) can help protect your data by encrypting your internet connection, making it harder for an attacker to intercept your traffic.

Strong router login credentials

Changing your router’s default login credentials can prevent an attacker from gaining control of your network.


Using browser extensions that force websites to use HTTPS can help protect your data by ensuring that your connection to websites is secure.

Public key pair based authentication

Using public key authentication can provide a higher level of security than password-based authentication.

Endpoint security

Using endpoint security solutions can help protect your devices from threats and provide visibility into potential attacks.

Awareness and training

Educating your team about the risks and signs of MitM attacks can help everyone be more vigilant and prepared.

Digital cyber attack simulation

And lastly, but certainly not least, regularly testing your systems and defenses with a simulated cyber attack from CovertSwarm can help identify vulnerabilities and prepare for real attacks.


Man-in-the-middle attacks are a serious threat. Understanding what they are, and how they work is crucial in maintaining the security of your data and systems. 

However, understanding is only the first step. To truly safeguard your systems, you need to be proactive. This is where CovertSwarm can help. Our ethical hackers can continuously probe your systems, simulating the tactics and techniques of genuine man-in-the-middle attackers. 

Secure your defenses. Choose CovertSwarm. 

Partner with our expert Swarm of ethical hackers to ensure your cybersecurity stance keeps pace with the bad actors. Contact us for more information about man-in-the-middle attacks.