Man-in-the-Middle Attack

How MITM Attacks Are Executed

In a Man-in-the-Middle attack, the attacker positions themselves between a client and server so that all communications pass through their system. Classic techniques include ARP poisoning (broadcasting false ARP replies to associate the attacker's MAC with the gateway's IP), DNS SpoofingAn attack that corrupts DNS cache entries to redirect domain name lookups to a malicious IP address. Also called DNS cache poisoning, it can silently redirect users to phishing sites without changing the URL in the browser. (redirecting DNS lookups to attacker-controlled servers), and rogue Wi-Fi access points that mimic legitimate networks.

Once in position, the attacker can read plaintext traffic, inject malicious content, strip EncryptionThe process of converting plaintext data into ciphertext using a cryptographic algorithm and key, making it unreadable without the corresponding decryption key. The foundation of secure communication on the internet. from connections, or harvest credentials. SSL stripping attacks downgrade HTTPSHTTP Secure. The encrypted version of HTTP that uses TLS to protect data in transit between a browser and a web server. Identified by the padlock icon in browsers and the https:// URL scheme. connections to HTTP by intercepting the initial redirect before the client establishes a TLS session.

Defenses Against MITM

HTTPS with proper SSL/TLS CertificateA digital document that binds a cryptographic key pair to an organization or domain, enabling encrypted HTTPS connections. Issued by Certificate Authorities (CAs) like Let's Encrypt, it proves a website's identity to browsers. validation is the primary defense. When a browser connects via TLS, the server's certificate is verified against trusted CAs — a certificate signed by an unknown CA triggers a hard warning. HSTS prevents SSL stripping by refusing unencrypted connections to HSTS-enabled domains entirely.

At the network level, Dynamic ARP Inspection (DAI) on managed switches prevents ARP poisoning. 802.1X port authentication prevents unauthorized devices from joining wired networks.

Why Public Wi-Fi Is Risky

Unencrypted public Wi-Fi networks are prime MITM attack venues. Any device on the same network can observe unencrypted traffic. Even encrypted Wi-Fi is vulnerable if the attacker knows the pre-shared key. Using a Proxy ServerAn intermediary server that forwards requests between a client and destination server. Forward proxies anonymize client traffic; reverse proxies sit in front of servers for load balancing, caching, and security. or VPN on untrusted networks provides an additional layer of protection for all traffic. Use DNS Leak Test to verify your DNS queries are not being intercepted or redirected on untrusted networks.