Information
The clr enabled option specifies whether user assemblies can be run by SQL Server.
Rationale:
Enabling use of CLR assemblies widens the attack surface of SQL Server and puts it at risk from both inadvertent and malicious assemblies.
Solution
Run the following T-SQL command:
EXECUTE sp_configure 'clr enabled', 0;
RECONFIGURE;
Impact:
If CLR assemblies are in use, applications may need to be rearchitected to eliminate their usage before disabling this setting. Alternatively, some organizations may allow this setting to be enabled 1 for assemblies created with the SAFE permission set, but disallow assemblies created with the riskier UNSAFE and EXTERNAL_ACCESS permission sets. To find user-created assemblies, run the following query in all databases, replacing <database_name> with each database name:
USE [<database_name>]
GO
SELECT name AS Assembly_Name, permission_set_desc
FROM sys.assemblies
WHERE is_user_defined = 1;
GO
Default Value:
By default, this option is disabled.
References:
https://docs.microsoft.com/en-us/sql/t-sql/statements/create-assembly-transact-sql