What Is a Man-in-the-Middle (MITM) Attack?
A Man-in-the-Middle (MITM) attack is a type of cyberattack where an attacker secretly intercepts and potentially alters communication between two parties. The attacker positions themselves between the two communicating parties, allowing them to eavesdrop on the conversation and potentially manipulate the data being exchanged. This can lead to data theft, credential compromise, and unauthorized access to systems.
An MITM attack can occur on any communication channel, including public Wi-Fi networks, compromised routers, or between client applications and servers. MITM attacks pose a significant threat because they are often difficult for victims to detect. By relaying or injecting malicious data between parties, attackers can impersonate one or both sides of the communication.
As online transactions and data exchanges increase, so does the importance of understanding and mitigating MITM attacks to maintain personal and organizational security.
This is part of a series of articles about website security.
In this article:
- Stages of a Man-in-the-Middle Attack
- Types of Man-in-the-Middle Attacks
- Recent Examples of Man-in-the-Middle Attacks
- Best Practices for Preventing Man-in-the-Middle Attacks
Stages of a Man-in-the-Middle Attack
A typical MITM attack unfolds in two main stages: interception and decryption.
- Interception
In this phase, the attacker gains access to the communication channel between two parties. This is commonly done through techniques like ARP spoofing (on local networks), DNS spoofing (redirecting traffic to malicious servers), or by setting up rogue Wi-Fi hotspots. The goal is to position the attacker’s device so that all traffic flows through it, allowing observation or manipulation of data. - Decryption or manipulation
Once the attacker has access to the data stream, they may decrypt encrypted traffic using various techniques such as SSL stripping or installing fraudulent certificates. In this phase, the attacker can read sensitive data, modify it in transit, or inject malicious payloads. If the traffic is unencrypted, they can directly observe or alter it with little effort.
Some MITM attacks may also include session hijacking or replaying captured messages to gain unauthorized access or impersonate users.
Types of Man-in-the-Middle Attacks
1. ARP Cache Poisoning
ARP (address resolution protocol) cache poisoning is a technique where an attacker sends falsified ARP messages onto a local network. These messages associate the attacker’s MAC address with the IP address of another device, typically the gateway or another trusted device. As a result, traffic meant for the legitimate device is misdirected to the attacker’s computer. This method is prevalent on local area networks and can be implemented with tools that automate the sending of spoofed ARP responses.
Once the attacker intercepts the traffic, they can monitor, modify, or inject malicious payloads into the data stream. Information stolen through ARP cache poisoning may include sensitive credentials, session cookies, or confidential communications. Since ARP lacks authentication mechanisms, devices will often accept poisoned entries without validation.
2. DNS Spoofing Attacks
DNS spoofing, also known as DNS cache poisoning, manipulates the domain name system (DNS) responses to redirect users from legitimate websites to malicious ones. Attackers insert false DNS records into the cache of a DNS resolver or the victim’s device, causing browsers to resolve domain names to IP addresses controlled by the attacker instead of the legitimate servers.
When users attempt to visit trusted websites, they unknowingly connect to the attacker’s fraudulent site. These fraudulent sites are often crafted to mimic legitimate websites closely, tricking users into entering sensitive information such as usernames, passwords, or credit card details.
DNS spoofing can also be used to intercept or manipulate data transmitted by applications relying on DNS. Since the process happens below the application layer, users typically see no warning or indication that their traffic is being redirected.
3. SSL/TLS Stripping and Downgrade Attacks
SSL/TLS stripping attacks target the security provided by HTTPS connections. The attacker intercepts web requests and downgrades them from HTTPS to HTTP, removing encryption without the user’s awareness.
When a user tries to access a secure website, the attacker connects to the real server using HTTPS but relays information to the user over unsecured HTTP. The attacker can then read, modify, or inject information into the communication stream as it passes through.
Downgrade attacks take advantage of protocol negotiation, coercing clients and servers to use less secure encryption methods. By forcing weaker ciphers, attackers make it easier to decrypt or manipulate the data. Both SSL stripping and downgrade attacks compromise the confidentiality and integrity of user communications.
4. Rogue Wi-Fi Access Points
A rogue Wi-Fi access point is a wireless network set up by an attacker, often with a compelling name that entices users to connect. Once users join the malicious access point, all their data traffic passes through the attacker’s system, granting them potential access to sensitive credentials, session tokens, or other personal information.
These attacks are particularly effective in cafes, airports, and hotels. Attackers frequently combine rogue access points with other MITM techniques, such as SSL stripping or DNS spoofing, to maximize data interception and manipulation. The unrestricted access to network traffic allows attackers to execute further attacks or track users’ browsing behaviors.
5. Email Hijacking and Phishing-Based MITM
Email hijacking-based MITM attacks occur when attackers compromise email accounts or intercept email traffic between a user and a trusted entity, such as a bank. By gaining access to email correspondence, attackers can manipulate communication threads, redirect funds, or deliver malicious attachments under the guise of legitimate contacts.
Attackers may also inject phishing links tailored to the ongoing conversation. Phishing-based MITM attacks extend beyond email, involving fake websites or man-in-the-browser malware that intercepts login credentials or financial data during legitimate transactions.
Learn more in our detailed guide to phishing protection.
6. Session Hijacking and Cookie Theft
Session hijacking involves stealing or predicting valid web session tokens to impersonate legitimate users. Attackers commonly intercept session cookies through techniques like network sniffing on unsecured Wi-Fi or deploying malicious code within browsers. Once attackers obtain a valid session identifier, they can bypass authentication mechanisms and gain unauthorized access to user accounts or online services without needing passwords.
Cookie theft is often carried out as part of MITM, where unencrypted web traffic or poorly secured session management allows attackers to capture authentication tokens. While modern browsers and services implement security measures like HTTPOnly and Secure flags, vulnerabilities in web applications or lax security configurations still make session hijacking prevalent.
7. Mobile Application MITM Vulnerabilities
Mobile applications are increasingly targeted by MITM attackers, especially those that do not correctly enforce certificate validation or transmit sensitive data in plaintext. Attackers leverage compromised Wi-Fi networks, DNS spoofing, or reverse proxying to intercept data sent between mobile apps and their back-end servers. If the applications do not properly check server certificates, attackers can present forged certificates and harvest data without users noticing.
Vulnerable mobile applications are especially problematic in financial, healthcare, and enterprise contexts, where leaked data can have severe consequences. Developers should adhere to secure coding practices, implement certificate pinning, and ensure end-to-end encryption is always enforced.
Related content: Read our guides to Socgholish
Recent Examples of Man-in-the-Middle Attacks
Here are recent real-world examples of man‑in‑the‑middle (MITM) attacks to illustrate current threats.
1. Salt Typhoon and U.S. Telecom Breach (2024–2025)
In mid‑2024 and early 2025, telecoms in the U.S. — including AT&T, Verizon, Lumen Technologies, and T-Mobile — were targeted by a state‑linked group called Salt Typhoon. Attackers executed MITM-style intrusions deep into carrier networks, enabling interception of voice calls and location tracking without detection. It compromised sensitive communications across business and government sectors and is considered the largest telecom hack in U.S. history.
2. OpenSSH Session Hijacking Vulnerabilities (February 2025)
Two new security flaws discovered in OpenSSH versions 6.8p1 through 9.9p1 (clients and servers) enable active MITM and denial‑of‑service attacks under specific configurations—especially when VerifyHostKeyDNS is enabled. These vulnerabilities prompted high‑urgency patches in February 2025.
3. Tesla Account Phishing & MITM (2024)
Security researchers demonstrated a phishing-based MITM attack targeting Tesla users. By tricking victims into registering a new “phone key,” they gained remote access to the vehicle—including unlocking and starting it—via interception of credentials through the mobile app (Tesla app version 4.30.6 / software 11.1 2024.2.7).
4. TrickBot’s shaDll Module (Late 2024 / Early 2025)
The TrickBot malware group, in collaboration with Lunar Spider and Wizard Spider, deployed the shaDll module, which installed fraudulent SSL certificates on victim systems. This enabled transparent interception of encrypted traffic, code injection, screenshot capture, and data exfiltration inside corporate networks.
5. Terrapin Attack on SSH Negotiation (2023–2024)
Discovered in December 2023, the Terrapin attack affects many OpenSSH installations. It uses downgrade and sequence-number manipulation during feature negotiation to break SSH channel integrity—effectively behaving like a MITM interception. As of early 2024, around 11 million publicly reachable SSH servers remained vulnerable until client and server updates were applied.
Sources: CrowdStrike, Palo Alto Networks, The Hacker News, Bleeping Computer, PureWL
Best Practices for Preventing Man-in-the-Middle Attacks
Organizations can implement the following practices to better protect themselves from MitM attacks.
1. Enforcing End-to-End Encryption
End-to-end encryption ensures that data sent between clients and servers remains confidential throughout transmission. Only the intended endpoints can decrypt and access the information, making it far more difficult for attackers to read or manipulate intercepted data. Protocols like HTTPS, SSH, and encrypted messaging standards (such as Signal Protocol) are essential for securing communication channels.
Organizations should enforce the use of strong encryption algorithms and regularly update their cryptographic libraries to protect against emerging vulnerabilities. Enforcing end-to-end encryption also involves disabling support for weak ciphers and mandating the use of secure negotiation protocols, such as TLS 1.2 or 1.3. Applications should not allow users to bypass security warnings about invalid certificates.
2. Multi-Factor Authentication for Critical Systems
Multi-factor authentication (MFA) adds an extra layer of security by requiring users to provide two or more forms of verification before accessing critical systems. Even if attackers intercept usernames and passwords via a MITM attack, they will not be able to authenticate without the additional factors—such as time-based one-time passwords (TOTP), mobile push notifications, or hardware tokens.
Implementing MFA should be mandatory for all sensitive systems, including administrative portals, financial services, and internal corporate resources. Organizations should educate users about the importance of MFA and consider supplementing it with adaptive authentication policies based on user behavior or device risk levels.
3. Monitoring, Detection and Incident Response
Continuous monitoring of network traffic and user activity is critical for early detection of MITM attacks. Security tools such as intrusion detection systems (IDS), network intrusion prevention systems (NIPS), and security information and event management (SIEM) platforms can identify anomalies, suspicious patterns, and signs of traffic interception. Real-time alerts prompt incident response teams to investigate potential MITM scenarios before attackers can cause damage.
In the event of a detected attack, organizations need a well-documented incident response plan. This plan should include isolating affected systems, blocking malicious traffic, and revoking compromised credentials or sessions. Conducting a thorough post-incident analysis helps identify the root cause and strengthens defenses for the future.
4. DNS Security Extensions (DNSSEC) Implementation
DNS security extensions (DNSSEC) are cryptographic protocols that protect DNS responses against tampering and forgery. By digitally signing DNS data, DNSSEC enables resolvers to verify the authenticity and integrity of DNS records, making it extremely difficult for attackers to execute DNS spoofing-based MITM attacks.
Organizations and service providers should enable DNSSEC for their domains and educate users about its importance in preventing redirection to malicious websites. Proper DNSSEC implementation requires careful configuration and management, including regular key rotation and validation of the entire DNS chain of trust. DNSSEC deployment protects internet users and improves the credibility of online businesses.
5. Regular Network Audits and Penetration Testing
Security teams perform audits to review configurations, patch missing updates, and evaluate protocol security. Penetration testing simulates real-world attack scenarios, testing defenses against MITM techniques such as ARP poisoning, rogue Wi-Fi deployment, and SSL stripping. The findings provide actionable insights for improving overall cybersecurity posture.
Network audits and penetration tests should be scheduled frequently and integrated into broader risk management frameworks. Organizations must promptly remediate findings and ensure all personnel follow established security policies.
Preventing MITM Attacks in the Enterprise with Seraphic Security
Seraphic Security addresses this challenge with a unique, enterprise-grade browser security platform that protects against MITM attacks at their source. By embedding advanced security controls directly into the browser layer, without requiring proxies, VPNs, or intrusive endpoint agents, Seraphic ensures that every user session is encrypted, authenticated, and continuously monitored for signs of tampering.
With Seraphic, enterprises gain full visibility into browser traffic while maintaining a seamless user experience. The platform defends against SSL stripping, session hijacking, credential theft, and malicious injections, safeguarding both corporate data and employee privacy. Because Seraphic supports all major browsers, including Chrome, Edge, Firefox, and even in-app browsers, organizations can achieve consistent protection across their entire workforce.
In short, Seraphic Security eliminates the blind spots where MITM attackers thrive, giving enterprises the confidence to enable secure, browser-based work—anywhere, on any device.
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