is there any security thread by using SQL "BCP" commands

Question

is there any security thread by using SQL "BCP" (xp_cmdshell 'bcp') commands?

Answer 1

When the xp_cmdshell extended stored procedure is enabled, an attacker could use it to run BCP commands to export sensitive data from the SQL Server. Additionally, an attacker could use BCP to import malicious data into the SQL Server, which could be used to execute arbitrary code, create a new user with administrator privileges, or cause a denial of service attack.

It is also possible to use BCP to run other command-line utilities on the host operating system by using the "queryout" option. This can allow an attacker to execute arbitrary code on the host operating system under the context of the SQL Server service account, which could provide the attacker with privileged access to the host operating system.

For these reasons, it is important to properly restrict access to the xp_cmdshell extended stored procedure and use secure authentication methods when using BCP. It is also recommended to use the least privilege principle and only run BCP with the necessary permissions.

Answer 2

Generally, it is recommended to have xp_cmdshell disabled. Whether that really is a security precaution can be disputed. In the default setting, xp_cmdshell is only available to members of the sysadmin role. For other users to use, you need to set up proxies.

The argument for having it disabled is that if you have an intruder coming in through an SQL injection hole through an application that uses a login which is sysadmin (which is very bad in itself), the intruder could use xp_cmdshell for attacks to other machines in your network. The counterargument is that if you are a sysadmin member, you can enable xp_cmdshell, so having it disabled does not really protect you that much.

Then again, you should think of which user is going to run that code? If the idea is that a plain application user is going to run BCP through xp_cmdshell, you will run into permissions issues, and you will have to set up a proxy. In that case, it may be better to run BCP directly from the client, without going through SQL Server.