A Man-In-The-Middle Attack (MITM) occurs when a malicious actor secretly intercepts and relays communication between two parties. This can happen during online transactions, where the attacker can capture sensitive information like passwords or credit card details without either party knowing. In a typical MITM scenario, the attacker may use techniques such as packet sniffing or session hijacking to gain access to the data being exchanged. To protect against these attacks, users should employ encryption methods, such as HTTPS, and be cautious about public Wi-Fi networks, which are often vulnerable to such threats.