Limiting the impact of a security breach of the endpoint, for example, when a system service or application gets compromised, is accomplished by restricting the permissions and privileges given to the exposed service or application. One way of doing this is by configuring the services and applications to run under dedicated, restricted user accounts. The more restricted the user account that the service or application runs under, the less reach it has into the operating system.
The following are instructions that detail how to run the FileZilla FTP service under a restricted user. Out of the box, this service runs under the Local System account, the highest privileged account in the Windows operating system: ...