I have installed antivirus and noticed that all https sites I am visiting use the certificate of antivirus's manufacturer. It looks like man-in-the-middle attack and I understand why the antivirus's manufacturer do it: it is only way to check https traffic and find threats.

But my knowledge is not enough to answer to next two questions:

• What is the new certificate? It is the certificate which was generated in my computer when I was installing the antivirus ? Or it is the one certificate for all users of this antivirus ?

• What are the new attack vectors with this substituted certificate ?