Access to common language runtime (CLR) code must be disabled or restricted unless specifically required and approved.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-271301 | SQLI-22-007300 | SV-271301r1109114_rule | Medium |
| Description |
| Information systems are capable of providing a wide variety of functions and services. Some of the default functions and services may not be necessary to support essential organizational operations (e.g., key missions, functions). It is detrimental for applications to provide, or install by default, functionality exceeding requirements or mission objectives. Applications must adhere to the principles of least functionality by providing only essential capabilities. SQL Server may spawn additional external processes to execute procedures that are defined in the SQL Server but stored in external host files (external procedures). The spawned process used to execute the external procedure may operate within a different OS security context than SQL Server and provide unauthorized access to the host system. The CLR component of the .NET Framework for Microsoft Windows in SQL Server allows users to write stored procedures, triggers, user-defined types, user-defined functions, user-defined aggregates, and streaming table-valued functions, using any .NET Framework language, including Microsoft Visual Basic .NET and Microsoft Visual C#. CLR packing assemblies can access resources protected by .NET Code Access Security when it runs managed code. Specifying UNSAFE enables the code in the assembly complete freedom to perform operations in the SQL Server process space that can potentially compromise the robustness of SQL Server. UNSAFE assemblies can also potentially subvert the security system of either SQL Server or the common language runtime. |
| STIG | Date |
| Microsoft SQL Server 2022 Instance Security Technical Implementation Guide | 2025-05-30 |
Details
| Check Text (C-75344r1108999_chk) |
| To determine if [CLR] is enabled, execute the following command: SELECT name, value, value_in_use FROM sys.configurations WHERE name = 'clr enabled' If [value_in_use] is a [1], review the system documentation to determine whether the use of [CLR] is approved. If it is not approved, this is a finding. |
| Fix Text (F-75251r1109000_fix) |
| Disable use of or remove any CLR code that is not authorized. To disable the use of CLR, from the query prompt: EXEC SP_CONFIGURE 'clr enabled', 0; RECONFIGURE WITH OVERRIDE; For any approved CLR code with Unsafe or External permissions, use the ALTER ASSEMBLY to change the permission set for the assembly and ensure a certificate is configured. |