Man-in-the-middle (MITM)

What Is an MITM Attack?

Man-in-the-middle (MITM) attacks represent a significant threat, capable of seizing control of communication sessions. In these attacks, an intermediary positioned between two parties covertly intercepts the session, manipulating the communication process without the parties' awareness. This enables the attacker to pilfer information or assume false identities to gain access to service systems. MITM attacks encompass various specific techniques, including Wi-Fi spoofing, email hijacking, DNS spoofing, and SSL hijacking. They are frequently utilized to pilfer personal data such as login credentials, emails, and financial accounts, wreaking havoc on online systems like e-banking, online gaming platforms, and digital transactions.

How Does an MITM Attack Work?

To illustrate an MITM attack, consider this scenario: Imagine you're at a café, using your laptop to browse the web. You scan for available Wi-Fi networks and find one named after the café. You connect to it to access the internet and proceed to log in to various online services. Despite receiving a warning from your browser about the connection's insecurity, you dismiss it and continue browsing. Unbeknownst to you, this situation could be an MITM attack in progress. Your online activities are being surveilled by attackers who have intercepted the connection. As a result, they can eavesdrop on your personal information, including account details, home addresses, and email addresses, putting your privacy and security at risk.

In the example provided, an MITM attack involves two main steps:

1. 1. An assailant endeavors to position themselves between two communicating parties to intercept their communication traffic. This enables them to pilfer data or utilize counterfeit identities to gain entry into service systems.

2. For instance, Wi-Fi spoofing, as mentioned earlier, is a prevalent technique employed in MITM attacks. When a user connects to the Internet via a counterfeit Wi-Fi router, all subsequent communication traffic traverses through this spurious Wi-Fi router, thereby enabling the attacker to monitor all online activities. Alongside Wi-Fi spoofing, other methods such as malware delivery, DNS spoofing, and ARP spoofing are frequently utilized in MITM attacks.

3. 2. Once inserted into the communication link, the attacker gains the ability to manipulate the communication between the two parties, initiating operations such as data theft or the use of counterfeit identities to access service systems.

4. In such scenarios, technologies like certificate forgery and traffic decryption may come into play. For instance, in the previous example, the attacker fabricates a certificate for the website server being accessed by the user and transmits this fraudulent certificate to the user's browser. Consequently, the browser is unable to verify the legitimacy of the certificate. Should the user proceed with accessing the site, the attacker establishes connections with both the user and the server clandestinely. Subsequently, the attacker can decrypt the traffic, enabling them to pilfer or manipulate the data without the user's awareness.

There Are Five Common Types of MITM Attacks

Attackers often leverage a variety of techniques to execute MITM attacks. The following section outlines common attack types and associated technologies.

Wi-Fi Spoofing

As previously discussed, one of the simplest and most commonly used methods to execute MITM attacks involves the creation of a malicious Wi-Fi access point. The attacker sets up an access point with a name that appears legitimate, such as that of a nearby cafe. This access point typically lacks encryption, making it vulnerable to exploitation. When an unsuspecting user connects to this malicious Wi-Fi access point, all subsequent communication traffic is intercepted by the attacker, allowing for the theft of personal information.

ARP Spoofing

ARP spoofing, alternatively known as ARP poisoning, involves the manipulation of a user's ARP cache by an attacker to reroute the user's traffic to the attacker's system. When LAN users initiate access requests, they are typically forwarded by a gateway. Initially, a user sends an ARP request to retrieve the MAC address associated with the gateway's IP address. Exploiting this, the attacker masquerades as the gateway and responds to the user with their own MAC address. Consequently, the user updates its ARP cache with the incorrect MAC address. As a result, all subsequent traffic from the user is unintentionally directed to the attacker's system.

DNS Spoofing

DNS spoofing, also known as DNS hijacking, involves tampering with the DNS resolution process to redirect users to fraudulent websites. Initially, when a user attempts to access the Internet, they send a DNS request to a DNS server to retrieve the IP address associated with a domain name. Subsequently, the DNS server responds with the mapping between the domain name and its corresponding IP address. However, attackers can intervene in this process by altering the IP address linked to the domain name, thereby redirecting user access.

In such scenarios, users remain unaware that they are being directed to a fraudulent website rather than the legitimate one they intended to visit. An infamous example of DNS spoofing involved an attacker compromising the DNS server settings of over 4 million computers via malware. By rerouting DNS requests to the attacker's DNS server, the attacker could return fake IP addresses for websites, resulting in an illicit income of US$14 million.

Email Hijacking

Attackers employ various methods to hijack the email servers of banks or financial institutions, which often host numerous user email accounts. By gaining unauthorized access to these servers, attackers can monitor users' email communications and, in some cases, impersonate the financial institution to send fraudulent emails to individual users. This tactic enables them to obtain sensitive user information and deceive users into conducting transactions such as unauthorized bank transfers.

For instance, a notable incident in 2015 involved attackers defrauding bank clients of 6 million euros in a certain country. During this attack, the perpetrators accessed bank email accounts and utilized malware or other forms of social engineering to deceive clients into transferring funds to fraudulent accounts.

SSL Hijacking

Presently, the majority of websites are accessed through HTTPS, wherein SSL connections are established between users and website servers, ensuring data integrity and confidentiality through SSL certificates. HTTPS adoption has helped mitigate MITM attacks to some extent. However, attackers persist in exploiting vulnerabilities, employing techniques like SSL hijacking to compromise HTTPS security.

SSL hijacking, also known as SSL certificate spoofing, involves an attacker forging a website server certificate, substituting the legitimate public key with their own, and presenting the fraudulent certificate to the user. Although the user's browser may warn of an insecure connection, if the user proceeds without due caution, the attacker gains control over the communication between the user and the server, enabling them to decrypt traffic and potentially manipulate or steal data.

Moreover, attackers may breach digital certificate issuers directly to pilfer genuine certificates from reputable websites. In a notable incident in 2011, a digital certificate issuer fell victim to such an attack, resulting in the theft of over 500 certificates from prominent websites, leading to a significant data breach and compromising the personal information of numerous users.

How Can MITM Be Prevented?

While MITM attacks come in various forms and are challenging to detect, there are measures we can implement to mitigate the risks. Below are some common strategies to prevent MITM attacks:

• Avoid connecting to public Wi-Fi networks indiscriminately. Only use known and trusted Wi-Fi networks to prevent the interception of traffic. Additionally, refrain from using default router passwords for personal Wi-Fi networks. Instead, employ strong cryptographic protection for passwords to deter cracking attempts.

• Verify that you are accessing websites using HTTPS. Consider installing the HTTPS Everywhere browser plugin, which automatically directs your browser to HTTPS versions of websites.

• Pay attention to security alerts indicating that a website's certificate is insecure. Ignoring such warnings may indicate that the website is compromised.

• Utilize VPNs for remote access to safeguard communication traffic from potential interception.

• Exercise caution with phishing emails, often designed to mimic trusted sources and prompt users to click on deceptive links. Avoid interacting with suspicious emails to prevent downloading malicious software or being directed to harmful websites.

• Keep antivirus software installed and up to date to mitigate the risk of malware infections.

• Implement firewalls and endpoint security solutions within enterprise networks to prevent malicious attacks. Additionally, provide security awareness training to employees to enhance their understanding of potential threats. Employ multi-factor authentication for service systems to bolster security measures and increase resilience against unauthorized access attempts.