InformationIt is recommended that SQL Server software be installed on a dedicated server. This architectural consideration affords security flexibility in that the database server can be placed on a separate subnet allowing access only from particular hosts and over particular protocols. Degrees of availability are easier to achieve as well - over time, an enterprise can move from a single database server to a failover to a cluster using load balancing or to some combination thereof.
It is easier to manage (i.e. reduce) the attack surface of the server hosting SQL Server software if the only surfaces to consider are the underlying operating system, SQL Server itself, and any security/operational tooling that may additionally be installed. As noted in the description, availability can be more easily addressed if the database is on a dedicated server.
NOTE: Nessus has not performed this check. Please review the benchmark to ensure target compliance.
SolutionUninstall excess tooling and/or remove unnecessary roles from the underlying operating system.
It is difficult to see any reasonably adverse impact to making this architectural change, once the costs of making the change have been paid. Custom applications may need to be modified to accommodate database connections over the wire rather than on the host (i.e. using TCP/IP instead of Named Pipes). Additional hardware and operating system licenses may be required to make these architectural changes.