In the current landscape of cyber attacks, data frequently ends up passing through hackers’ systems. While phishing and ransomware seek to deceive users into giving away credentials or directly stealing information from systems, Man-in-the-Middle (MitM) attacks operate differently. It involves an invisible third party attempting to impersonate each of two communicating parties, capturing and potentially altering the exchanged information without detection.
Attackers have the capability to intercept web sessions, such as those between a user and an online payment service or data exchanged between machines, applications, virtual servers, or physical servers. Imagine making a large payment transfer to a trusted supplier when suddenly an outsider intervenes in the transaction and discreetly changes the bank details. You believe your payment is secure; however, it is actually being redirected to a criminal’s account. This scenario illustrates how Man-in-the-Middle (MiTM) attacks operate in practice.
What Man-in-the-Middle (MITM) Attack is
In 2024, MiTM attacks made up 23% of cyber incidents related to identity. Although their elusive nature often leads them to be underestimated, it’s important not to dismiss the threat they pose. These attacks can result in various malicious activities including large-scale fraud, account takeovers (ATOs), and financial losses. It is essential for businesses to adopt effective strategies that prevent these types of attacks in order to safeguard both the company and its customers.
For a malicious actor, the key element of an attack is discovering methods to intercept communication. They take advantage of network vulnerabilities by deceiving individuals into connecting with compromised networks—such as mimicking nearby Wi-Fi names—or steering users towards counterfeit websites that closely resemble legitimate ones through DNS traffic manipulation. Over time, these attacks have become increasingly sophisticated, evolving from simple eavesdropping on unencrypted Wi-Fi connections to exploiting network protocols and targeting APIs.
MitM attacks aren’t just focused on stealing sensitive information or altering messages. They can also include injecting harmful content into communications or impersonating others in digital interactions, such as social platforms or dating apps, which could lure victims into dangerous situations.
For instance, a news article from April 2024 disclosed that an Indian antivirus service distributing user updates through HTTP was attacked by a cybercrime group using MiTM tactics. The attackers intercepted the antivirus update files, altered them, and deployed malware onto users’ systems.
Several Types of Man-in-the-Middle Attacks
1. Email Hijacking
In MitM attacks, email hijacking entails intercepting communications between two parties over email without directly accessing their accounts. Attackers use strategies like spoofing email addresses or exploiting vulnerabilities in email protocols to manipulate these exchanges. This manipulation often allows them to redirect funds or modify payment information. Additionally, they may insert false information into the conversation threads, causing confusion and miscommunication that can have a significant impact on businesses.
2. Wi-Fi Eavesdropping
Wi-Fi eavesdropping occurs when cybercriminals intercept data transmitted over wireless networks. A common tactic is the use of rogue access points, often called “evil twins,” which are deceptive replicas of legitimate networks. When unsuspecting users connect to these fake networks, attackers can capture unencrypted information such as login details, credit card numbers, and personal messages.
Even without modifying the data, attackers can collect information by passively observing communications through unauthorized access points. This intelligence-gathering technique could be used in future targeted assaults. Such attacks are common in public spaces like cafes, libraries, and airports where individuals frequently connect to unsecured Wi-Fi networks without considering security concerns.
3. Session Hijacking
Session hijacking occurs when an attacker assumes control of a user’s active session with a web application, typically by obtaining their session tokens or cookies. This malicious activity can be executed using techniques like cross-site scripting (XSS) or packet sniffing on unsecured networks. Once the attacker gains access to an active and valid session, they have the ability to carry out any actions that the legitimate user is authorized to do, such as making purchases or transferring funds.
4. SSL Stripping
SSL stripping is a technique that reduces a secure HTTPS connection to an unsecured one without the user’s knowledge. In this process, the attacker intercepts the user’s request to visit a website and provides them with an insecure replica of it while passing information back and forth with the real site. This allows attackers to collect sensitive data like login credentials, all while making victims think they are communicating safely. SSL stripping is particularly successful against users who do not notice when their browser’s address bar lacks HTTPS.
5. DNS Spoofing/Poisoning
DNS spoofing is a technique where DNS responses are altered to steer traffic away from legitimate services towards malicious sites. This attack involves corrupting the DNS cache of a resolver or server, allowing the attacker to intercept and modify communications between systems. Typically, attackers leverage vulnerabilities in the DNS protocol to introduce fraudulent DNS responses into the resolver’s cache.
Understanding Man-in-the-Middle Attack Techniques
Threat actors are both resourceful and adaptable in their methods for executing Man-in-the-Middle (MitM) attacks. Here are some of the tactics they commonly employ:
- Compromising a certificate authority (CA) is a form of Man-in-the-Middle (MiTM) attack. In this scenario, attackers infiltrate the CA system to issue fake SSL/TLS certificates. As a result, malicious websites seem legitimate because they have seemingly valid certificates. This allows threat actors to intercept HTTPS traffic without arousing suspicion since browsers will recognize and trust these fraudulent certificates just like genuine ones from authentic sites.
- Packet sniffing involves utilizing tools to monitor and intercept data packets traveling across a network. This process typically employs software such as Wireshark or tcpdump, which can capture traffic in real-time. After an attacker has gained access to the network—often through techniques like ARP spoofing or by enticing users into connecting with rogue access points—they are able to examine the intercepted packets and potentially extract sensitive information.
- Man in the browser—This method involves inserting harmful code into a user’s web browser, often through seemingly legitimate but malicious browser extensions. This malware captures data exchanged between the user and web applications, enabling attackers to alter requests and responses without the user’s knowledge.
- ARP spoofing involves sending deceptive ARP messages across a local network. These fraudulent messages enable attackers to link their MAC address with the IP address of a legitimate device, allowing them to intercept and manipulate traffic intended for that device.
- API Vulnerability: Attackers take advantage of unsecured APIs to intercept and alter requests. These security vulnerabilities may involve APIs that fail to use HTTPS for secure communication or are publicly accessible without adequate access controls. Exploiting these weaknesses can result in unauthorized access to sensitive data exchanged between different services.
6 Ways to Prevent Man-in-the-Middle Attacks
1. Strong Encryption Protocols
Encryption protocols like HTTPS and TLS (Transport Layer Security) are essential for protecting data as it travels across networks. They secure information exchanged between clients and servers by encrypting the communications, making any intercepted data unreadable to potential attackers.
It is crucial to utilize the latest versions of these protocols, particularly TLS. Alarming research from 2023 revealed that as many as 79% of online servers still employ outdated TLS versions susceptible to MiTM attacks. Conduct a comprehensive network audit to pinpoint any services using older protocol versions and deactivate them. Employ tools such as SSL Labs’ SSL Test for assessing your server’s TLS version and configuration effectively.
2. DNSSEC
DNSSEC provides a crucial security enhancement to DNS queries, preventing attackers from intercepting or falsifying DNS responses. By using cryptographic keys to sign DNS records, it enables resolvers to confirm the authenticity of received responses. If an attacker tries to redirect users by modifying DNS replies with malicious intent, the resolver can identify and detect such tampering.
3. Dynamic ARP Inspection with DHCP Spoofing
Dynamic ARP Inspection (DAI), when used in conjunction with DHCP snooping, effectively safeguards against ARP spoofing attacks commonly employed in Man-in-the-Middle scenarios. DAI ensures that only legitimate ARP packets are validated on the network, preventing attackers from linking their MAC address to a genuine IP address. Paired with DHCP snooping—which filters out untrusted DHCP messages—this approach stops unauthorized devices from acquiring an IP address within the network.
4. Virtual Private Networks (VPNs)
A VPN secures all data exchanged between a user’s device and the VPN server through encryption, making it extremely difficult for attackers to intercept or decode the information. This is especially crucial for remote employees accessing sensitive company data or customers conducting transactions over unsecured Wi-Fi networks. While VPNs can play an essential role in your data governance strategy, they are not completely safe from MitM attacks if improperly configured, particularly when issues arise with encryption, configuration settings, or vulnerabilities on the user’s device.
5. API Security
Review the OWASP list of common API security vulnerabilities. Adopt best practices including robust authentication and authorization protocols like OAuth 2.0, passwordless login methods, and API keys to guarantee that only authorized clients have access to sensitive endpoints.
Conducting regular security evaluations, such as penetration tests and vulnerability assessments targeted at API endpoints, can help detect and address weaknesses before they are exploited by malicious actors.
6. User Education and Awareness
Like many aspects of cybersecurity, tackling the human element through enhanced education and awareness can be highly beneficial. Encourage both employees and customers to look for the padlock icon when browsing online as a sign of secure connections. Additionally, educate them on the risks associated with insecure connections such as open public Wi-Fi networks, and explain how using a VPN can protect information transmitted over those networks.
During sales demos, you can convey important awareness tips and showcase some of your security measures to reassure prospective customers that their data is a priority. Emphasize the significance of using strong, unique passwords and enabling additional authentication factors.
Countering Man-in-the-Middle Threats
Foundational security practices such as encryption and multi-factor authentication (MFA) continue to be crucial for protecting against various Man-in-the-Middle (MitM) techniques. However, there are instances where these measures alone may not be sufficient.
In many cases, MitM attacks include impersonation or fraudulent websites. Memcyco’s Digital Risk Protection (DRP) solutions are highly effective at detecting such impersonation attempts by tracking suspicious activities and identifying real-time instances of your website being cloned. This proactive approach helps avert expensive MitM threats associated with fake sites.
