A security administrator has a server environment where most files don't change much, and the administrator wants to implement a solution that monitors for changes. What should the security administrator implement?

Implementing File Integrity Monitoring (FIM) is the most appropriate solution in this scenario because it specifically focuses on monitoring and detecting changes to files. Given that the server environment has files which don't change much, FIM is designed to alert the security administrator whenever there are unauthorized modifications, deletions, or additions to these files. This capability is essential for maintaining the integrity of critical data and ensuring that any unexpected alterations are quickly identified and addressed.

FIM tools work by creating a baseline of file attributes—such as checksums, size, and modification dates—and then continuously monitoring the files against this baseline. If any discrepancies are detected, alerts can be generated, allowing for timely investigation and response. This proactive approach to monitoring file integrity is crucial in environments where data security is a priority, especially when protecting sensitive or critical information.

Other options might have their purposes in a broader security strategy, such as preventing data leaks (DLP), detecting network intrusions (IDS), or aggregating and analyzing security event data (SIEM). However, none of these focuses specifically on monitoring changes to files in the way that FIM does. Hence, FIM stands out as the most effective and tailored solution for the given requirement.