Security information and event management (SIEM) explained

What is SIEM? 

Security information and event management (SIEM) is an advanced cybersecurity solution designed to centrally aggregate and correlate security data from various sources within your network. SIEM plays a crucial role in protecting against sophisticated cyberattacks and ensuring compliance.

Gartner® introduced the term SIEM in 2005 to address the necessity for centralized security monitoring. Today, SIEM solutions cater to a wide range of enterprise security requirements, including advanced threat detection and compliance. They also provide operational management capabilities such as incident management, reporting, and security analytics dashboards.

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Why SIEM?

Security professionals often face challenges in aggregating security data from various applications and devices across the network. They frequently lack comprehensive visibility, which is crucial for promptly detecting and addressing cyberthreats, assessing the impact of cyberattacks, and proactively enhancing their network’s security posture.

Unlike other security solutions that focus on specific functionalities, SIEM is a configurable security platform that provides a comprehensive overview of both on-premises and cloud environments. SIEM tools significantly improve security visibility, enable real-time threat detection, and facilitate compliance management, thereby strengthening network security. By integrating artificial intelligence (AI), these tools automate remediation processes, predict adversaries’ next steps, and reduce the workload of security analysts. They provide actionable insights and empower security teams to counter adversarial techniques effectively

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How SIEM works

The most fundamental function of any SIEM tool is to aggregate security data points, primarily logs and events, in a centralized location. If you opt for an on-premises SIEM solution, your data will be hosted on a server and at a later point archived within a secondary storage device for easy retrieval. If you opt for a cloud-based SIEM solution, your data will be stored in the cloud in the vendor’s environment. Centralized log data aggregation is a key strength of any SIEM solution because it provides security analysts with comprehensive visibility across the network and facilitates forensic analysis at a later stage.

The second primary function of a SIEM solution is to analyze the collected data and deliver actionable insights. This analysis employs various techniques, including correlation, behavior analytics, and trend visualization. Real-time correlation enables analysts to link multiple seemingly unrelated events to identify patterns for effective threat detection, which is a core function of any SIEM tool. Behavior analytics, often powered by machine learning or AI, helps establish baselines for user and entity behaviors and activities to detect anomalies, thereby enhancing threat detection accuracy. SIEM tools typically combine static detection rules with anomaly models to detect threats with high precision and accuracy.

Additionally, SIEM solutions support continuous security monitoring for change management and user activity monitoring use cases, which are essential for most compliance requirements. With log data archiving, forensic analysis, and security monitoring features, adopting a SIEM solution becomes a crucial component of any compliance journey.

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Essential SIEM use cases for modern security operations

Enterprise security operations tailor their security use cases based on factors such as organizational size, business nature, security maturity, and industry sector. Gartner advises maintaining a well-structured and continuously improving set of security use cases to ensure they remain valuable and relevant to security operations, rather than becoming obsolete documents. Formulating strong security use cases drives the implementation of SIEM solutions.

SIEM solutions, serving as the central hub for security data, are among the most effective tools for implementing a wide range of security use cases. Their orchestration and integration capabilities make them particularly valuable for threat detection, compliance management, and continuous monitoring.

According to Gartner, security use cases can be broadly classified per the below figure.

SIEM solutions help you meet all three categories of these use cases—threat detection, compliance and continuous monitoring, and forensic investigation and threat hunting.

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Top SIEM use cases to implement

SIEM for threat detection

Malicious insider threat detection

Detect suspicious insider activities, such as unusual access to a critical resource, data exfiltration attempts, or abnormal logons, using the behavioral analytics capability of SIEM systems. Integrate a user risk management system with behavioral analytics to detect slow and persistent insider attacks, account compromises, and more.

Compromised user detection

Spot credential leaks or unusual usage of a user account to detect user account compromises. Fine-tune your SIEM detection rules to monitor indicators of attack, such as logons from unusual locations or at unusual times or multiple logons within a short span of time from different geolocations. This can help you detect compromised user accounts.

Advanced persistent threat detection

Detect advanced and complex threats, like lateral movement, privilege escalation, data exfiltration, or credential access, using correlation rules and machine-learning-driven anomaly detection. Mapping rules to the MITRE ATT&CK threat modelling framework's tactics and techniques helps assess the threat coverage you get out of SIEM implementation.

Known threat detection

Look for SIEM solutions that have built-in integration with threat intelligence platforms to enhance their known threat detection capabilities. SIEM tools often come with a rich threat repository of their own to detect malicious IP addresses, URLs, domains, and indicators of compromise. They also offer playbooks to detect and instantly mitigate known threats.

SIEM for controls and compliance monitoring

The essence of controls and compliance monitoring is data aggregation and the ability to generate audit reports out of it. SIEM systems play a crucial role in this by providing real-time visibility into security events; generating compliance reports for mandates like the PCI DSS, HIPAA, the GDPR, SOX, and FISMA; and ensuring data protection by design.

Further, to facilitate effective user activity monitoring, SIEM solutions track changes to user credentials and access patterns to detect unauthorized changes and ensure compliance with internal policies. SIEM solutions collect and audit system and security logs, making it easier to generate detailed compliance reports and conduct forensic analysis in the event of a security breach.

SIEM for forensics and threat hunting

SIEM systems enhance forensic analysis and threat hunting in security operations through their search and correlation functions. They enable batch searches on historical log data, assisting security teams in investigating past incidents and identifying patterns or trends. By leveraging historical correlation and search capabilities, SIEM software reveals long-term trends and patterns crucial for effective forensic analysis. Additionally, the security analytics features of SIEM software, including automated incident timelines, process lineage visualizations, attack path visualizations, and contextual user mapping, facilitate comprehensive analysis of security events and efficient threat hunting.

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Role of SIEM in cybersecurity

SIEM functions as a comprehensive security platform rather than a single solution offering specific capabilities. Since its inception by Gartner in 2005, SIEM has evolved significantly, continually adapting to the dynamic changes and needs of the market.

Initially a simple approach to log and compliance management, SIEM has transformed into a next-generation technology. The key distinctions between SIEM and other technologies, particularly threat detection and response solutions like EDR, network detection and response (NDR), and extended detection and response (XDR), are as follows:

• Holistic approach

  SIEM encompasses data collection and analysis, operating independently from other vendors that often rely on additional technologies for effective functioning.

• High customizability

  No single solution can meet the diverse security needs of different industries. To ensure optimal security, it is essential to customize and fine-tune the security solution to the specific requirements of the enterprise. SIEM platforms are highly customizable.

• Integration

  SIEM solutions act as a security hub, aggregating data from all parts of the network. They are highly scalable and flexible, particularly with the shift to cloud-based solutions. Cloud SIEM solutions, with extensive integration and high-speed analytical capabilities, can provide enterprises with timely insights.

  Explore Log360's integrations  

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How SIEM differs from other security tools

Often, SIEM solutions are compared with other evolving security tools, such as security orchestration, automation, and response (SOAR) and XDR. Enterprises frequently face confusion regarding which tool to select and for which specific needs. The table below illustrates the fundamental differences between log management, SOAR, XDR, and SIEM solutions. To choose an appropriate security solution, we recommend reviewing your security requirements, considering the use cases for which you need a security tool, assessing deployment methods, and determining the resources you plan to invest.

SIEM vs. SOAR: What's the difference?

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SIEM benefits for enterprises and small businesses

SIEM for security teams

SIEM empowers security teams with real-time visibility into network activities, enabling rapid threat detection and response. By correlating vast amounts of data, SIEM solutions help identify anomalies, suspicious activities, and potential attacks. This enhanced situational awareness allows security teams to prioritize incidents, reduce response times, and improve overall security posture.

SIEM for IT operations

SIEM offers IT operations teams valuable insights into system performance and health. By monitoring logs from various IT components, teams can identify potential issues, optimize resource utilization, and ensure service availability. SIEM solutions also aid in capacity planning, troubleshooting, and compliance reporting, streamlining IT operations.

SIEM for business leaders

SIEM provides business leaders with a comprehensive overview of the organization's security posture and risk landscape. By quantifying security risks and demonstrating compliance with industry regulations, SIEM helps protect the company's reputation and bottom line. Additionally, SIEM can help optimize IT investments by identifying areas for improvement and demonstrating the value of security initiatives.

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Looking to implement a SIEM solution?

Are you considering implementing a SIEM solution? Here are some quick steps you need to consider.

Pre-deployment checklist:

1. Formulate security use cases

Document and maintain the security use cases for which you are considering deploying a SIEM solution. This will help you choose the right deployment method for the SIEM solution and fine-tune its capabilities to meet your needs.

2. Ascertain resources

Assess and come to a conclusion about the resources you are ready to invest in deploying and maintaining a SIEM solution. This includes hardware spending as well as paying the analysts who will be using the SIEM deployment. If you have a small security operations team and a limited budget for hardware spending, go for a cloud-based SIEM solutions since they are easy to maintain with no upfront hardware spending.

3. Choose the deployment method

SIEM solutions come with various deployment options, including on-premises deployment, cloud SIEM solutions, and managed SIEM solutions. Depending on the resources and your organization's security maturity, choose the deployment method that best suits you.

Deployment checklist:

4. Ingesting the right data

Be it compliance monitoring or threat detection, your SIEM solution works best if you configure the right data sources and ingest the right data into it. Most false positives in SIEM are attributed to poor data ingestion practices. Sit with your SIEM vendor or managed service provider to provide visibility into your environment and configure the data right.

5. Configuring detection rules

Depending on the use cases you've chosen, test and configure correlation and anomaly rules. Remember to optimize the rules regularly as your environment keeps changing.

6. User access setup

Set up user accounts and role-based access to your SIEM solution based on your defined access control policies.

7. User training

Provide ongoing training to users of the SIEM solution for optimal utilization and to ensure they are proficient in using it.

Post-deployment maintenance

8. Continuous monitoring

Continuously monitor the performance of the SIEM solution and match it with your goals. Ensure that your SIEM solution is collecting and processing data as expected.

9. Alert management

Review and respond to alerts generated by your SIEM software. Set up a procedure to handle alerts based on criticality or business division to address issues immediately.

10. Performance tuning

Regularly check the efficacy of detection rules and keep optimizing them to reduce false positives and improve the accuracy and precision of detection.

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AI in SIEM: Overcoming challenges

Vendors are integrating AI into their SIEM systems to enhance threat detection, predictive analytics, and automated responses. AI-driven SIEM solutions address the current challenges of SIEM deployment, including false positive generation, increased response time, and lack of proactive security implementation. With AI capabilities, SIEM solutions can:

• Improve accuracy by reducing false positives through smart thresholds.
• Enhance security analytics with predictions, enabling proactive security approaches.
• Accelerate incident response by bringing in security telemetry and impact analysis based on criticality, and by suggesting remedies for neutralizing threats.

Improve accuracy by reducing false positives through smart thresholds. Enhance security analytics with predictions, enabling proactive security approaches. Accelerate incident response by bringing in security telemetry and impact analysis based on criticality, and by suggesting remedies for neutralizing threats.

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