A man-in-the-middle (MITM) attack occurs when a cybercriminal positions themselves between a user and a service, intercepting the data that flows between them. The attacker can eavesdrop on conversations, steal sensitive information like passwords or payment details, or modify messages in transit.
Common scenarios include:
- Connecting to unsecured public WiFi networks, where an attacker captures unencrypted data from nearby users
- Redirecting traffic through a fake website that mimics a legitimate service
- DNS spoofing, where attackers direct users to fraudulent servers
- ARP (Address Resolution Protocol) spoofing on local networks
Why it matters: MITM attacks are particularly dangerous because both the user and the legitimate service remain unaware that communication has been compromised. This makes them effective for stealing login credentials, financial information, or sensitive business data.
How to protect yourself:
- Only use HTTPS websites (look for the padlock icon), which encrypts data end-to-end
- Avoid conducting sensitive transactions over public WiFi
- Use a reputable VPN (virtual private network) to encrypt all traffic
- Verify SSL certificates on websites before entering credentials
- Enable two-factor authentication on important accounts
- Keep your operating system and browser updated with security patches
A common gotcha: MITM attacks can sometimes bypass single-factor authentication entirely, which is why services now encourage two-factor methods. Even if attackers intercept your password, they cannot access your account without the second authentication factor.