A Security Information and Event Management (SIEM) system is a foundational tool in modern security operations. Its primary purpose is to provide a centralized view of an organization's security posture. It achieves this by aggregating log data and event information from a wide array of sources, such as servers, firewalls, and applications. The SIEM then normalizes this data and applies correlation rules and analytics to identify patterns, anomalies, and potential threats that would be invisible when looking at individual systems. This process enables the generation of real-time alerts, allowing security analysts to detect and respond to incidents promptly and effectively.

A. SIEMs are powerful tools that augment and streamline threat hunting by providing correlated data, but they do not replace the need for skilled human analysts.

B. The core value of a SIEM lies in its ability to actively analyze, correlate, and interpret logs, not just passively collect them for compliance archives.

D. This describes the primary function of an Endpoint Detection and Response (EDR) or antivirus (AV) solution, which operates directly on endpoints to block and remove malware.

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1. National Institute of Standards and Technology (NIST). (2006). Guide to Computer Security Log Management (Special Publication 800-92). Section 2.4, "Log Analysis Tools," describes the functions of centralized log analysis, which are the basis for modern SIEMs, including "log reduction, log conversion, centralized log correlation," and the ability to "generate alerts."

2. Bhatt, S., & Manadhata, P. K. (2013). Security Information and Event Management (SIEM): A brief introduction. In IEEE Security & Privacy, Courseware from the University of Washington, CSE 599. This course material defines SIEM as a technology that provides "real-time analysis of security alerts generated by network hardware and applications," emphasizing the aggregation, correlation, and alerting functions.

3. Microsoft Documentation. (2023). What is a SIEM?. Microsoft Azure. In its official documentation explaining the concept, Microsoft states, "A SIEM...gathers data from across the enterprise's network...It then uses analytics to correlate the data, identify anomalous behavior, and prioritize threats." This directly supports the functions of aggregation, correlation, and alerting.

4. Al-Harbi, M., Al-Turki, M., & Al-Shehri, W. (2021). A Survey on Security Information and Event Management (SIEM) Correlation Rules. Electronics, 10(16), 1907. Section 2, "SIEM Architecture and Components," states, "The main functions of SIEM are to collect data from different sources, normalize the collected data, and then correlate the events to detect security attacks." (https://doi.org/10.3390/electronics10161907)