As a SQL Server enthusiast, I often come across various tools and techniques that can make our lives easier. However, when it comes to security, there are certain practices that I highly recommend avoiding. One such practice is the use of the native xp_cmdshell commands in SQL Server.

The xp_cmdshell command allows you to execute operating system commands directly from within SQL Server. While it may seem convenient, it poses significant security risks and can potentially expose your server to malicious attacks. Even the SQL_Server_2012_Security_Best_Practice_Whitepaper advises against using xp_cmdshell whenever possible.

So, what are the alternatives? Let me show you two ways to achieve similar functionality without compromising security.

T-SQL Way

The first approach involves using standard T-SQL commands. Here’s an example:

-- To allow advanced options to be changed.
EXEC sp_configure 'show advanced options', 1
GO

-- To update the currently configured value for advanced options.
RECONFIGURE
GO

-- Disable xp_cmdshell option now
EXEC sp_configure 'xp_cmdshell', 0
GO

RECONFIGURE
GO

This method works well when you have direct access to the SQL Server box and want to disable xp_cmdshell on that specific server.

PowerShell Way

For administrators managing multiple servers in a datacenter, executing a T-SQL script line-by-line or server-by-server is not practical. In such cases, PowerShell can be a powerful tool. Here’s an example of a PowerShell script that checks if xp_cmdshell is enabled on a server:

[Reflection.Assembly]::LoadWithPartialName("Microsoft.SqlServer.Smo") | Out-Null;
$srv = new-object Microsoft.SqlServer.Management.Smo.Server("MSSQLSERVER")

if ($srv.Configuration.XPCmdShellEnabled -eq $TRUE)
{
    Write-Host "xp_cmdshell is enabled in instance" $srv.Name
}
else
{
    Write-Host "xp_cmdshell is Disabled in instance" $srv.Name
}

This script uses the SQL Server Management Objects (SMO) library to connect to the server and check the status of xp_cmdshell. You can easily modify this script to loop through multiple servers and gather information about their xp_cmdshell status.

By leveraging PowerShell, administrators can efficiently manage and monitor the configuration of xp_cmdshell across their entire environment.

I encourage you to try out these methods and share your experiences. Have you ever used similar scripts in your environments? Let me know!