Man-in-the-Middle Attack

A Man-in-the-Middle Attack (MITM), also known as an interception attack, occurs when an attacker secretly positions themselves between a user and a blockchain service or another party. The attacker intercepts communication, relays it, and potentially alters it without detection. For example, during a cryptocurrency transaction, the attacker swaps the recipient's wallet address with their own.

Attackers achieve this by exploiting network vulnerabilities. They use techniques like ARP spoofing to impersonate the gateway on a local network, creating fake Wi-Fi hotspots to lure users, or compromising DNS to redirect traffic. The attacker decrypts, reads, or modifies data in transit—such as transaction details—then forwards it. Victims see normal operation, but the attacker controls the flow.

MITM attacks matter greatly in cryptocurrency because they undermine transaction security. Users risk sending funds to attackers instead of intended recipients. Public blockchains rely on accurate address verification; any swap leads to irreversible theft. Exchanges and wallets vulnerable to unsecured connections face high risks.

Key characteristics include stealth—the attack evades detection by mimicking legitimate traffic. Types split into passive (eavesdropping only) and active (altering data). Prevention involves HTTPS, VPNs, verifying addresses manually, and hardware wallets that sign transactions offline.