What is Man in the Middle (MitM) Attacks? Types and How to Prevent Them

Suppose you're engaged in an online chat with a close friend, discussing plans for the weekend. Unknown to both of you, a third party has been a part of this exchange without your knowledge. Days later, you discover fraudulent transactions on your bank statement, a chilling realisation that your casual conversation was compromised. This type of cyber attack is known as Man in the Middle attack (MitM). In Man in the Middle attacks, an attacker intercepts and potentially modifies communication between two unsuspecting parties.

This can lead to the theft of sensitive information such as passwords, financial data and personal identification for individuals and intellectual property, financial fraud and customer data breaches for organisations. Hence, understanding MitM threats is essential for maintaining the privacy, security and trustworthiness of our online interactions.

Understanding Man in the Middle Attacks

An MitM attack is a cybersecurity breach where an unauthorised third party intercepts the communication between two entities without their knowledge, often with the intention of modifying the communication. Attackers initiate Man in the Middle attacks by intercepting the first step in a data exchange to include themselves into the communication circuit. Once they gain access, they can filter and steal the data before passing it along, potentially modifying it without the knowledge of the original parties.

Interception is the method by which attackers gain access to private communications in Man in the Middle attacks. By positioning themselves in the data flow between sender and receiver, attackers can silently capture and analyse the data passing through.

Types of MitM Attacks

Man in the middle attacks pose a significant threat to data privacy and integrity. The following are some of the most common types of MitM attacks:
●    Passive eavesdropping - Passive eavesdropping involves an attacker quietly listening to private communications without the knowledge of the parties involved. The attacker aims to gather sensitive information by intercepting data transmitted between two entities. 

●    Active interference - Active interference occurs when an attacker inserts themselves into the communication process between two parties, actively manipulating the data being exchanged, leading to misinformation, fraud or unauthorised transactions. 
●    Wi-Fi eavesdropping - Wi-Fi eavesdropping exploits the vulnerabilities of insecure public Wi-Fi networks to intercept data. Attackers monitor network traffic in places like cafes, airports and hotels, capturing any unencrypted data that passes through. 

●    SSL striping - SSL stripping targets the secure communication channel between a user and a website by downgrading HTTPS connections to less secure HTTP.
●    DNS spoofing - DNS spoofing involves redirecting traffic from a legitimate website to a fraudulent one, created by the attackers, by corrupting the DNS server's address resolution process.

Preventing MitM Attacks

While understanding the types of Man in the Middle attacks is crucial, it’s equally important to know how to prevent them. Here are some key strategies and practices that can significantly reduce the risk of falling victim to MitM attacks:

●    Encryption: Encryption ensures that data transmitted over the internet is unreadable to unauthorised interceptors. HTTPS and SSL/TLS protocols encrypt the data between a user's device and the server, safeguarding our sensitive information.

●    Virtual Private Networks (VPNs): VPNs create a secure and encrypted path for internet traffic, shielding data from potential interceptors.

●    Regular updates: Keeping software and systems up to date is critical in preventing MitM attacks. Cyber attackers often exploit vulnerabilities in outdated software to intercept communications. 
●    Secure practices: Awareness about the risks of public Wi-Fi, the importance of using HTTPS websites and recognising phishing attempts are significant to reduce the likelihood of falling victim to MitM attacks.
●    Wi-Fi security: Implementing robust Wi-Fi security measures is essential in reducing the risk of MitM attacks. This includes using strong, complex passwords, enabling WPA3 encryption on networks and hiding the network SSID.

●    Multi-factor authentication (MFA): MFA adds an extra layer of security, making it significantly more challenging for attackers to gain unauthorised access even if they manage to intercept or steal credentials.

Advanced Prevention Techniques

In addition to the basic prevention techniques, there are also advanced strategies that can provide a higher level of security against Man in the Middle attacks. These techniques often require more technical expertise but can significantly enhance the security posture of a network or system:
●    Network security tools: Using firewalls, intrusion detection systems (IDS) and intrusion prevention systems (IPS) helps monitor and control network traffic to prevent unauthorised access and detect potential MitM attacks.

●    Certificate pinning: Certificate pinning enhances mobile app security by ensuring the app communicates only with the verified server, preventing attackers from intercepting data through forged certificates.
●    Regular security audits and testing: Regularly assessing and testing an organisation's security infrastructure identifies vulnerabilities and strengthens defences against MitM and other cyber attacks.

Conclusion

Man in the Middle attacks, which involve an attacker secretly intercepting and possibly altering the communication between two parties without their knowledge, pose significant threats to the confidentiality, integrity and availability of information. We should have a comprehensive approach to safeguard ourselves against these threats by emphasising on encryption, secure connections, the deployment of network security tools and other best practices.

Such attacks demand a commitment to continuous learning, awareness and the adoption of strong security measures. Implementing strong, layered security measures and promoting a culture of security awareness can significantly reduce the risk of Man in the Middle attacks and other cyber threats. Together we can protect our digital interactions and preserve the integrity of our online communications.