What is primarily monitored by an Intrusion Detection System?

An Intrusion Detection System (IDS) is specifically designed to monitor network operations to detect potential attacks and suspicious activities. The primary function of an IDS is to provide security by identifying unauthorized access or anomalies in the network traffic that could indicate a breach or an attempted attack. It analyzes incoming and outgoing network packets, looking for patterns that match known threats or behaviors that deviate from the norm.

Monitoring network operations allows the IDS to react to real-time threats, providing alerts and detailed logs that enable security teams to respond promptly. This is crucial in safeguarding sensitive data and maintaining the security posture of the organization.

While the other options involve important aspects of security, they do not align with the core function of an IDS. For instance, monitoring system files for unauthorized changes typically falls under the domain of host-based security measures rather than network-focused detection. User activity for compliance relates to ensuring adherence to policies or regulations and is often handled by different compliance tools. Application performance metrics focus on the efficiency and speed of software applications, which does not address security threats directly. Thus, the role of an IDS distinctly centers on the surveillance of network operations for potential intrusions.