What can a hacker do if he steals a site's SSL certificate?

Question

Burglary protection

Hello, what can a hacker do if he gets an SSL certificate
and has it in the form of files:

• AddTrustExternalCARoot.crt
  
• site.csr
  
• site.key
  
• site_net.crt
  
• PositiveSSLCA2.crt

And what should you do if all the same, these certificates have already been stolen and are now in bad hands?

Answer 1

It will be able to decrypt the traffic between you and the clients, if, of course, it can intercept it.
What are you waiting for? Get a new SSL from your ISP and be done with it. Change business 10 minutes
Etozh free until paid.
If the server is hacked and the certificates are stolen, why would he decrypt the traffic to hack the server?

Answer 2

Let's just say, before he steals, he'll have to hack into your server. Well, if he hacks it, then everything that the root user of the server can do. Regenerate keys and certificates, change what is available to the server, and make sure this doesn't happen again.

Answer 3

If I issue a new certificate, will he be able to find out about this? And How ?
They stole it, but I don’t know how, now I’m looking at the logs.