An Intrusion Prevention System (IPS) indeed does many of the things listed, including baseline analysis, signature-based blocking, and real-time traffic correlation with SIEM solutions. However, its defining role is to actively prevent intrusions by identifying malicious activity as it happens and taking automated actions to stop the threat. Because of this, the best single answer is D. An IPS must be able to terminate suspicious connections, block IP addresses, and otherwise intervene in real time, which distinguishes it from a passive detection solution.
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A) While some IPS solutions might incorporate heuristic analysis and behavioral monitoring, this is more characteristic of advanced threat detection systems or User and Entity Behavior Analytics (UEBA). The core function of an IPS is real-time prevention.
B) This describes the function of an Intrusion Detection System (IDS) combined with firewall capabilities. An IDS detects intrusions but doesn't actively block them. Firewalls use signatures to block known bad traffic. While an IPS might use signatures as one method, its defining characteristic is active prevention.
C) This describes the role of a Security Information and Event Management (SIEM) system. SIEMs collect logs and events from various security devices to provide a broader view of security incidents and enable threat hunting. An IPS might feed data to a SIEM, but that's not its primary role.