Steve,
I tried -x, but unfortunately I had a fresh crash with -x on.

Eirikur,
I am using mixed authentication mode, but ALL MY DATABASES ARE CONTAINED...

Ok Jeff, thank you.

PS: The firewall was the standard Windows Advanced Firewall.

In a new crash in another server (SQL 2016 CU6) I got the following error:

2017-12-11 10:14:22.60 Server  Error: 17066, Severity: 16, State: 1.
2017-12-11 10:14:22.60 Server  SQL Server Assertion: File:...

Hello Steve,

Microsoft docs notices:
Warning: When you use the –x startup option, the information that is available for you to diagnose performance and functional problems with SQL Server is greatly...

Connections are unencrypted, but each user has access only to his database. I use contained databases. Do you think the reason for an access violation can be a hacking attack?...

How can I check a hacking attempt?
I know for sure that the period with the crashes the server was known to hackers, and there were attempts to login...

Hello Eirikur,
No errors in Windows Event Log. I am including the errors of 14 Stack dumps of only ONE Server:

* BEGIN STACK DUMP:                               
* 11/26/17 17:19:39 spid...