What is security information and event management (SIEM)?

SIEM works by continuously collecting security data from sources throughout your environment, normalizing it into a consistent format, and analyzing it to identify threats and security incidents. The system ingests logs from firewalls, intrusion detection systems, endpoints, cloud services, and applications. It then applies correlation rules to connect related events that might indicate an attack. When the SIEM identifies suspicious patterns or matches known threat indicators, it generates alerts for your security team to investigate.

The SIEM process involves several steps:

• Data collection: Agents and connectors gather logs and events from every part of your infrastructure in real time
• Normalization: Raw data is converted into a standardized format so information from different sources can be compared and analyzed together
• Correlation and analysis: The system applies rules and machine learning models to identify relationships between events and detect anomalies that indicate threats
• Alert generation: When the analysis identifies potential security incidents, the SIEM creates prioritized alerts based on severity and risk
• Investigation support: Security analysts use the SIEM’s search and visualization capabilities to examine alerts, reconstruct attack timelines, and determine appropriate responses
• Response coordination: The SIEM can trigger automated responses or guide analysts through incident response workflows

SIEM platforms consist of several integrated components that work together to collect data, detect threats, and coordinate responses. Each component serves a specific function in the overall security monitoring and incident response process.

Log management is central to SIEM, handling the collection, storage, and indexing of massive volumes of event data from across your infrastructure. The SIEM aggregates logs from operating systems, databases, network devices, security tools, and cloud services into a centralized repository where they can be searched and analyzed. This unified log store provides the historical context needed to investigate incidents, identify attack patterns, and meet compliance requirements for data retention.

Threat detection capabilities analyze incoming data streams to identify security incidents as they occur. SIEM systems use multiple detection methods, including signature-based rules that match known attack patterns, behavioral analytics that identify deviations from normal activity, and machine learning models that recognize subtle indicators of compromise. Google Threat Intelligence feeds enrich this analysis by providing context about adversary tactics, malware families, and emerging threats.

Alerting transforms detected threats into actionable notifications for your security team. The SIEM evaluates each identified issue against risk-scoring criteria and organizational priorities to determine alert severity and routing. Mandiant Digital Threat Monitoring can extend your alerting capabilities by monitoring external sources for threats targeting your organization.

Response capabilities help security teams contain and remediate identified threats. SIEM platforms provide case management features that guide analysts through investigation and response workflows, tracking actions taken and maintaining an audit trail for each incident. Mandiant Consulting services can help you develop effective response playbooks to rapidly investigate, contain, and remediate cyber incidents.

Automation and orchestration reduce the manual effort required to process alerts and respond to common threats. Security orchestration, automation, and response (SOAR) capabilities allow you to define workflows that automatically execute multi-step response procedures when specific conditions are met. For example, when the SIEM detects malware on an endpoint, an automated playbook might quarantine the device, collect forensic evidence, scan other systems for similar indicators, and create a ticket for analyst review.

Threat hunting capabilities let security analysts proactively search for threats that evaded automated detection. The SIEM provides query interfaces and visualization tools that allow hunters to explore your environment, test hypotheses about attacker behavior, and uncover hidden compromises. Mandiant Threat Detection and Hunting services leverage the SIEM platform to systematically search for advanced threats.

Compliance features help you meet regulatory requirements and industry security standards. The SIEM automatically collects and retains logs according to compliance mandates like HIPAA, PCI DSS, GDPR, and SOX, providing the evidence auditors need to verify your security controls. Pre-built compliance reports map your log data to specific regulatory requirements, showing which systems are compliant and flagging gaps that need attention.

Successful SIEM implementation requires careful planning and a phased approach:

1. Define clear objectives: Identify specific security and compliance goals you want to achieve with the SIEM, such as detecting ransomware attacks, monitoring privileged access, or meeting PCI DSS requirements.
2. Assess your environment: Document all systems, applications, and data sources that need to feed into the SIEM, prioritizing critical assets and high-value targets.
3. Select appropriate data sources: Start by integrating the most important log sources like domain controllers, firewalls, and endpoint security tools before expanding to less critical systems.
4. Configure data collection: Set up agents, connectors, and APIs to reliably collect logs from identified sources without impacting system performance.
5. Normalize and enrich data: Configure parsing rules to extract relevant fields from raw logs and enrich events with contextual information about assets, users, and threat intelligence.
6. Develop use cases: Create detection rules and correlation logic tailored to threats facing your organization, starting with high-priority scenarios.
7. Tune detection rules: Test and refine rules to reduce false positives while maintaining sensitivity to genuine threats.
8. Establish workflows: Define investigation and response procedures for different incident types, documenting roles, responsibilities, and escalation criteria.
9. Train your team: Provide comprehensive training on the SIEM platform, investigation techniques, and response procedures.
10. Monitor and optimize: Continuously review SIEM performance, alert quality, and response metrics, making adjustments as needed to improve effectiveness.

SIEM supports diverse security scenarios across organizations, from threat detection to compliance management. Security teams leverage SIEM capabilities to address both immediate security needs and long-term operational challenges.

Common use cases of SIEM include:

1. Analyzing voluminous data sources: The rapid adoption of cloud and IoT means more security telemetry and the need to ingest breach-indicating server logs like DNS and DHCP. SIEM can analyze voluminous and demanding data sources with sub-second search across petabytes of data, providing the scale needed to cover all your bases across modern infrastructure.
2. Extended endpoint telemetry retention: You may consider the data from your EDR tool to be the single source of truth for every device across your network. However, due to high cost, there may be times when you cannot retain your EDR data for an extended period. SIEM allows you to ingest and store endpoint telemetry at least ten times longer and correlate it with broader enterprise signals for greater visibility and deeper analytics.
3. Automated response and orchestration: Response time is the difference maker in any unfolding security incident. Yet many organizations lack automation and orchestration capabilities, resulting in delayed and manually intensive efforts to respond to threats. A unified SecOps platform outfits your team with automated playbooks, case management, and collaboration that can result in faster and more effective responses.

Selecting the right SIEM requires careful evaluation of how different solutions align with your organization’s specific security needs, infrastructure, and resources. You need to consider both technical capabilities and operational factors like deployment complexity, ongoing maintenance requirements, and total cost of ownership. The best SIEM for your organization balances detection effectiveness, scalability, and usability while integrating seamlessly with your existing tools.

Use the following criteria to help evaluate SIEM solutions:

• Scalability: Verify the platform can handle your current log volumes and grow with your organization without performance degradation
• Integration capabilities: Look for pre-built connectors to your existing security tools, cloud platforms, and enterprise applications
• Detection effectiveness: Evaluate the sophistication of correlation rules, machine learning models, and threat intelligence integration
• Automation support: Determine how easily you can build automated response workflows and integrate with orchestration platforms
• Compliance support: Confirm the solution includes reports and features aligned with your regulatory requirements
• Total cost of ownership: Calculate licensing costs, infrastructure requirements, and staffing needs for implementation and ongoing operations

The future of SIEM will be shaped by increased automation, deeper integration across security tools, and more sophisticated analytics powered by artificial intelligence. We see SIEM evolving from a standalone platform into unified security operations that seamlessly combine threat detection, investigation, and response with extended detection and response (XDR) and security orchestration. Machine learning will continue advancing beyond simple anomaly detection to provide predictive capabilities that identify attacks in their earliest stages–well before significant damage occurs. As organizations adopt more cloud services and distributed architectures, cloud-native SIEM solutions will become the standard, offering greater scalability and built-in integration with cloud security controls.

Whether you need a complete managed SIEM service or want to leverage specific capabilities, Google Security Operations offers flexible options to meet your security operations requirements. We provide comprehensive SIEM capabilities that can handle massive log volumes with cloud-native scalability, advanced analytics that reduce false positives, and tight integration with the broader Google Cloud security ecosystem. Google Security Operations includes built-in data connectors that integrate seamlessly with your existing security tools and services, eliminating the complexity of custom integrations.