TempDB And TDE

Bob Ward troubleshoots an oddity around sys.databases marking tempdb as encrypted even when no user databases are encrypted:

In my test I did not hit the breakpoint. And furthermore, you will notice that when you query sys.dm_database_encryption_keys, there is no row for tempdb at all.  So our debugger breakpoint proves that tempdb is not permanently encrypted. Instead, if ALL user databases have TDE disabled and you restart SQL Server, tempdb is no longer encrypted. So instead of using sys.databases, use sys.dm_database_encryption_keys to tell which databases are truly enabled for encryption. I then verified my findings in the source code. Basically, we only enable encryption for tempdb if 1) ALTER DATABASE enables any user db for TDE 2) When we startup a user database and have encryption enabled. I also verified the behavior with my colleagues in the Tiger Team (thank you Ravinder Vuppula). We will look at fixing the issue with sys.databases in the future (ironically as I said earlier it was never enabled for tempdb before SQL Server 2016).

Read on for Bob Ward’s patented Debugger Fun.  My takeaway from this is that sys.dm_database_encryption_keys is valid, whereas sys.databases’s is_encrypted column might not be.

Related Posts

Non-Administrative Powershell Remoting And January 2019 LCU

Emin Atac tests out a security change made in the January 2019 Latest Cumulative Update for Windows: My first concern was: if it’s a security vulnerability, what’s its CVE? The blog post answer is: CVE-2019-0543 discovered by James Forshaw of Google Project Zero My second concern was twofold. Is the chapter about A Least Privilege Model Implementation Using Windows PowerShell published in the […]

Read More

xp_cmdshell And Non-Sysadmin Accounts

Lucas Kartawidjaja shows us how you can grant a non-sysadmin user the right to run xp_cmdshell: Once we run the above T-SQL query, any account that is part of the sysadmin role in the SQL Server instance has the ability to run the xp_cmdshell extended stored procedure. On the background, when the user with sysadmin […]

Read More

Categories

January 2017
MTWTFSS
« Dec Feb »
 1
2345678
9101112131415
16171819202122
23242526272829
3031