4min. read

What Is Security Information and Event Management (SIEM)?

What Is SIEM?

Originally designed as a tool to assist organizations with compliance and industry-specific regulations, security information and event management (SIEM) is a technology that has been around for almost two decades. It combines security information management (SIM) with security event management (SEM) and provides the foundation for cybersecurity threat detection capabilities. SIEM technology helps to manage security incidents through the collection and analysis of log data, security events and other event or data sources. Security operations center (SOC) analysts use SIEM tools to manage security incidents, and detect and respond to potential threats quickly.

According to Gartner, businesses looking for SIEM today need the solution to collect security event logs and telemetry in real time for threat detection, incident response and compliance use cases, with the ability to analyze the telemetry to detect attacks and other flagged activities. SIEMs also provide the ability to investigate incidents, report on activities, and store the relevant events and logs.

SIEM solutions help security teams to:

  • Collect, enrich and store data

  • Apply correlation and analytics

  • Investigate and mitigate threats

  • Provide data insights and reporting

How Does SIEM Work?

SIEM software brings together event and log data from end-user devices, servers, network infrastructure, security devices and applications, and aggregates the data into a centralized platform for easy access. Data collected can then be sorted into designated actionable categories that can recognize deviations from normal activity. This makes it easier for incident response teams to identify threats and investigate security alerts and incidents. SIEM solutions can be deployed on-premises, hybrid, and more increasingly, cloud-based. Cloud-based SIEMs offer faster and simpler deployment, and can scale automatically to accommodate increases in data sources or data ingestion.

SIEM Capabilities

A SIEM’s main functionality is to aggregate loads of data and consolidate it into one system for searchability and reporting purposes. The key capabilities a SIEM provides that are most useful to enterprises include:

  • Ingesting data for monitoring, alerting, investigation and ad hoc searching.

  • Profiling behavior across the organization.

  • Correlating data to look for unusual behavior and system anomalies.

  • Aggregating security-related events as they are generated.

  • Detecting advanced threats and adding context to security events.

  • Searching and reporting from data for advanced breach analysis.

  • Analyzing incidents and investigating breaches.

  • Reporting for compliance purposes.

SIEM Use Cases

Data Aggregation

A SIEM primarily collects data from servers and network device logs, but is more effective when used to aggregate data from endpoint security, network security devices, applications, cloud services, authentication and authorization systems, and online databases of existing vulnerabilities and threats. SIEM tools help businesses as they scale by ensuring visibility is not lost across applications, databases, users, devices and even third parties.


SIEM tools can be used to monitor user activity with context by analyzing access and authentication data and receiving alerts when suspicious behavior or violations of policies have been identified. This privileged user monitoring is a common requirement for compliance reporting across most regulated industries.

Threat Prevention

Security teams use SIEM tools to solve common and advanced security use cases. SIEM software correlates the aggregated data repository to look for unusual behavior, system anomalies and other indicators of a security incident. This information can then be used for real-time event notification, historical trend analysis and post hoc incident forensics. 

Data Storage

In addition to normalizing and organizing data, SIEM solutions have the ability to store historical log data for the long term. This not only helps with compliance but also enables correlation of data over time to assist security analysts with forensics and investigations in the event of a data breach.

Limitations of SIEM

SIEMs have long overpromised and under-delivered in their ability to detect and respond to cybersecurity threats. SIEM tools can be expensive and resource intensive, and it can be difficult to resolve problems with SIEM data. User and entity behavior analysis (UEBA) is an analytic tool developed to help fill the gap that SIEMs have in identifying anomalies and detecting unknown or advanced security threats beyond traditional malware. Another SIEM shortcoming is the lack of effective incident response. Businesses need to evaluate and consider SIEM vendors based on their own needs and capabilities in order to avoid overwhelming their security teams with too many alerts, false positives and misaligned infrastructure.

Do I Really Need a SIEM?

For organizations that may not have the expertise or the resources to implement, manage, maintain and monitor a SIEM solution, there are other options that may be worth researching, such as managed security services (MSS) and managed detection and response (MDR) services. Central log management is a solution that can be a first step toward a SIEM and helps to provide a centralized view into log data. Log data provides a record of everyday activity across an organization and can help with troubleshooting issues and supporting broader business needs. While log management helps to aggregate log data, a SIEM provides much more capability, and therefore a business should determine what it truly needs in order to ensure the functionality meets their expectations to avoid overpaying.

The Future of SIEM

Stopping today’s threats requires a radically new approach to security operations. The new category of extended security intelligence and automation management, or XSIAM, reimagines how organizations find and remediate threats using AI and automation. XSIAM was built with a vision to create the autonomous security platform of the future, driving dramatically better security with near-real time detection and response. With XSIAM, security teams manage intelligence and automation, rather than needing to manually manage information and events. 

The Cortex family of products – including Cortex XSIAM, Cortex XDR, Cortex XSOAR and Cortex Xpanse – offers AI-driven, scalable and comprehensive security for the SOC of the future.


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