The hacker changed the bank account and sent an email to the buyer, the buyer paid the money without understanding, what kind of cyber attack is this?

The scenario you've described sounds like a combination of social engineering and possibly email spoofing, but it doesn't fit neatly into a single category of cyberattack. Here's a breakdown of what might be happening:

1. Social Engineering: In this case, the hacker manipulated the buyer into paying money to a different bank account. Social engineering involves manipulating people into divulging confidential information or taking specific actions. In this scenario, the hacker likely used deception or manipulation to trick the buyer into changing the payment details.

2. Email Spoofing: It's possible that the hacker used email spoofing to make their email appear as if it came from a trusted source, such as the seller or the seller's bank. This can make it more convincing to the buyer. Email spoofing involves sending emails that appear to come from a different source than they actually do.

3. Phishing: While not explicitly mentioned in your scenario, phishing is often involved in social engineering attacks. Phishing involves sending deceptive emails that typically contain malicious links or attachments. In this case, the deceptive email might have contained instructions to change the bank account details.

4. Unauthorized Access: If the hacker gained unauthorized access to the seller's email or financial systems to make these changes, it could also be considered a form of hacking.