Security Information and Event Management (SIEM): A complete guide

Security Information and Event Management systems provide a centralised solution for monitoring, detecting, and responding to security threats in real-time. By collecting and analysing log data from various IT systems and security tools, SIEM Security Information and Event Management help identify anomalies and potential breaches that individual tools might miss.

It reduces the burden of false positives and enables cybersecurity teams to focus on the most critical threats. This guide will help you understand how Security Information and Event Management enhances your organisation’s security posture and how to choose and implement the right solution. Keep reading to know more!

Introduction to Security Information and Event Management

SIEM is a comprehensive solution that combines threat detection, real-time monitoring, and incident response across an organisation’s IT infrastructure.

SIEM systems analyse and collect data from various sources—such as networks, servers, and applications—to identify potential security threats and respond to them quickly.

By centralising security data, SIEM provides a unified view of security events, helping organisations mitigate risks, ensure compliance with regulatory standards, and detect anomalies. It’s a key tool for maintaining robust cybersecurity in an increasingly complex digital landscape.

What is Security Information and Event Management?

SIEM is a comprehensive tool for improving an organisation’s Cyber Security posture by giving you real-time visibility and control over its entire IT environment.

SIEM systems collect data from multiple sources, such as applications, servers, firewalls, and other network devices, allowing you to detect threats, respond to incidents, and ensure compliance with security standards.

For example, if there’s a failed login attempt or suspicious data transfer, a Security Information and Event Management solution will alert your security service provider so they can respond immediately. It not only helps you detect ongoing attacks but also allows you to investigate past incidents, providing a full picture of what occurred and how it affected your systems.

How do Security Information and Event Management work?

SIEM systems help you monitor your entire IT environment by collecting and analysing data from various sources, such as servers, devices, and applications. SIEM provides a centralised view of your network's security, helping you detect potential threats, investigate incidents, and respond to security issues in real-time.

Here’s how SIEM works, step by step:

1. Data collection

The first step in SIEM is gathering data from multiple sources within your network. SIEM collects logs (records of events) and event data from devices such as:

• Network equipment (routers, switches)
• Security Intelligence devices (firewalls, intrusion detection systems)
• Servers (web servers, mail servers)
• Applications (software running on your network)
• Service cloud call centre (software and services not hosted on your premises)

SIEM systems use various methods to collect this data, such as deploying collection agents on devices or using protocols like Syslog (a standard for sending log data), SNMP (Simple Network Management Protocol), or WMI (Windows Management Instrumentation). These methods allow the system to capture detailed information about what is happening across your network.

2. Data storage

Once the data is collected, it needs to be stored for analysis. Early SIEM systems had limited storage capabilities, often relying on expensive, on-premises storage. However, modern SIEM platforms use cloud-based storage to handle larger volumes of data at a lower cost. This allows you to retain and analyse all of your log data rather than just a small portion, making your SIEM system more effective at identifying security incidents.

3. Data analysis and correlation

After storing the data, the SIEM system starts analysing it. This is where the power of SIEM really comes in. The system uses predefined rules and policies (set by your SIEM cyber security team) to determine what is considered "normal" behaviour and what constitutes a potential threat. For example, the SIEM can flag events like multiple failed login attempts, unusual data transfers, or unauthorised access to sensitive systems.

SIEM systems also use correlation to link related events from different parts of your network. For instance, if a failed login on a server happens at the same time as a blocked connection on a firewall, SIEM will combine these data points to identify them as part of a potential security threat. This correlation helps in detecting patterns of suspicious behaviour that might otherwise go unnoticed.

4. Alerting and incident response

When SIEM identifies a potential security issue, it generates an alert. These alerts can be configured based on the severity of the threat and can notify your SOC immediately. For example, if the SIEM system detects potential malware or an account change that seems suspicious, it will send an alert to your team for further investigation.

In some cases, modern SIEM systems can automatically take action to contain the threat—like suspending a user account or blocking a suspicious connection. This feature is part of what’s known as Security Orchestration and Automation Response (SOAR), which allows your SIEM system to respond to security incidents with minimal human intervention.

5. Behavioural analysis

Today’s advanced SIEM platforms go beyond simple rule-based detection. They incorporate User and Entity Behavior Analytics (UEBA), which uses machine learning to understand typical patterns of behaviour within your organisation.

This allows the system to detect anomalies—like a user accessing data they wouldn’t normally access—that could indicate a security threat. Over time, the system learns what normal behaviour looks like for each user and device, improving its ability to catch unusual activity.

6. Forensic investigation

SIEM systems also provide tools for forensic investigation, allowing you to dig into past incidents to understand how a breach occurred, which systems were affected, and how the attacker moved through your network. All the log data is stored in the SIEM database, giving you a detailed record that you can analyse to prevent similar incidents in the future.

Benefits of Security Information and Event Management

SIEM systems analyse data from various sources across your IT infrastructure, enabling security teams to identify potential threats more efficiently. Here are the benefits you can expect from a SIEM solution:

Enhanced threat detection

A SIEM solution improves threat detection by collecting data from multiple sources, such as network devices, servers, and applications, and then analysing this information in real time. By correlating different events, SIEM systems can identify potential security threats that may go unnoticed when viewing isolated incidents. This holistic view allows you to detect suspicious activities and take action before they escalate.

Efficient incident response

SIEM platforms help security teams respond to threats more efficiently. When a security event occurs, the system generates alerts and provides insights into the event's context, helping your team quickly determine the severity of the threat.

The solution automates parts of the response process, allowing security teams to concentrate on the most urgent threats and reduce the time it takes to address them. This mitigates the impact of incidents and further helps you recover faster.

Centralised data management

One of the main advantages of SIEM is that it consolidates all security data in one centralised location. Instead of manually gathering data from different systems, SIEM systems automatically collect and store logs from across your infrastructure.

This makes it easier to monitor and analyse the data, saving time and reducing the chances of missing important information. The centralisation also supports historical data analysis, which can be useful for identifying trends and conducting thorough investigations.

Reduced false positives

SIEM systems reduce the number of false alerts, which can overwhelm your security team and make it harder to detect real threats. Advanced SIEM platforms can filter out non-critical alerts and ensure that security teams focus only on genuine threats. This helps prevent wasted time on false positives, allowing you to improve your detection accuracy and manage your resources more effectively.

Improved compliance management

Compliance is a significant concern for many organisations, and SIEM solutions can help simplify the process. By automatically collecting and analysing security data, SIEM solutions ensure that your organisation meets regulatory requirements.

They provide tools for monitoring compliance, generating reports, and documenting incidents, helping you stay aligned with industry standards. This reduces the burden of audits and ensures your security posture remains strong.

Scalability and flexibility

Modern SIEM platforms are highly scalable and can adapt to your growing IT environment. Whether your infrastructure includes on-premise systems, cloud platforms, or a hybrid environment, SIEM solutions integrate seamlessly with various technologies. As your organisation expands, an SIEM system can accommodate more data sources and maintain its effectiveness without requiring significant changes to the system.

Cost efficiency

SOC and SIEM can help reduce the overall cost of security management. By automating routine tasks like log collection, event correlation, and threat detection, SIEM systems reduce the workload for your security team.

This improved operational efficiency lowers the need for additional staff and resources. Moreover, the ability to respond to incidents quickly can help prevent costly breaches, downtime, and the associated financial and reputational damage.

Challenges and limitations of Security Information And Event Management

 Implementing and maintaining a SIEM system is not without its challenges. Some of these include:

Integration difficulties

SIEM tools are just one part of your broader cybersecurity infrastructure. Integrating them seamlessly with your existing security tools, like firewalls or antivirus software, can be challenging.

If these systems don't work well together, your SIEM might fail to give you a complete view of potential threats. To avoid this, you’ll need to ensure that data flows smoothly between different systems, which requires careful planning and often custom adjustments.

Complex configuration

Setting up a SIEM system to meet your specific needs can be complicated. During implementation, you need to determine which data sources to connect, configure correlation rules (which link related events across different systems), and adjust alert thresholds.

Getting these configurations right is critical. Errors in this process can lead to too many false positives (unnecessary alerts) or missed threats. It requires skilled personnel and time to fine-tune the system properly.

Unexpected costs

While SIEM solutions can improve security, they often come with hidden costs. As your organisation grows, so does the volume of data the SIEM system needs to process and store. 

This increase in data can lead to unforeseen expenses, especially if your SIEM solution wasn’t designed to handle large data volumes. These extra costs can strain your budget and impact the efficiency of your deployment.

Resource demands

Implementing SIEM solutions can be resource-intensive. You will need to allocate time, skilled personnel, and a significant budget. Smaller organisations, in particular, may find it difficult to commit these resources. This often forces companies to prioritise what areas of cybersecurity are most critical for their SIEM deployment.

Scalability issues

As your organisation grows, your SIEM system needs to scale to handle increasing amounts of data. Some SIEM solutions struggle with scaling up and might become less effective over time. 

If your SIEM can't keep up with the rising volume of security events, it could miss important alerts or slow down your response times. To avoid this, you should ensure that the SIEM solution you choose can handle your long-term growth.

Data onboarding challenges

Bringing all your organisation’s relevant data into the SIEM system can be difficult. Different systems and applications generate logs in various formats, and the process of making sure that data is standardised (called data normalisation) can be time-consuming.

If data is not onboarded correctly, the SIEM might not be able to detect threats accurately. You will need to develop a strategy for efficiently handling and normalising data from various sources to get the most out of your SIEM system.

Choosing the right Security Information And Event Management solution

As cyber threats evolve, having a robust system to monitor, detect, and respond to these risks becomes essential. Here are some essential factors to consider when assessing different SIEM options:

Real-time threat detection and monitoring

The ability to detect and respond to threats in real time is critical. Your SIEM should allow you to monitor network activity as it happens and send alerts about any suspicious activity. This immediate response capability can help prevent a minor security incident from becoming a major issue. Timely detection is essential for minimising damage, especially when dealing with fast-moving threats.

User activity monitoring

Insider threats are often overlooked but can be highly damaging, whether intentional or accidental; actions from within the organisation pose significant risks. User activity monitoring tracks all user behaviour, ensuring that any unusual actions are identified promptly. This is especially important for privileged users—employees with higher levels of system access. Monitoring helps prevent misuse and is often a requirement for meeting compliance standards.

Scalability

Your SIEM should grow alongside your organisation. As your company expands, so will your data and infrastructure needs. Choose a SIEM solution that can scale seamlessly without incurring unexpected costs. Some solutions base their fees on the amount of data processed, which can become expensive as your data volumes grow. Instead, consider solutions that charge based on the number of devices or data sources, providing better cost predictability.

Threat detection across all systems

Organisations use a variety of technologies to operate, from Linux and Windows servers to databases, web services, and applications. Your SIEM must be capable of normalising (standardising) and correlating (linking) data from all these sources into a common format for meaningful analysis. Ensure the solution you choose supports customised feeds, allowing it to handle legacy applications and unique systems.

Integration with other security tools

Your security solution should work in harmony with your existing tools. A strong SIEM integrates easily with other systems like antivirus software, login data, and security auditing software. This helps create a holistic view of your network, streamlining your IT team’s efforts by reducing the need to manually juggle different security tools.

Best practices for implementing SIEM

Implementing a Security Information and Event Management (SIEM) system can significantly improve your organisation’s security. However, to ensure a smooth and efficient implementation, it's essential to follow specific best practices. Here are some key strategies to keep in mind:

Define clear objectives

Before you begin the implementation process, establish specific goals for your SIEM system. Are you focusing on threat detection, regulatory compliance, or real-time monitoring? Defining clear objectives helps you prevent unnecessary expansion of the project scope. This clarity is crucial to ensure that the SIEM delivers the results you need without wasting resources.

Assess your IT infrastructure

Evaluate your current IT infrastructure to understand the amount of data the SIEM will handle. This includes logs from devices like servers, firewalls, and applications. You'll need to measure two metrics:

• Gigabytes per day (GB/day): The amount of data generated daily.
• Events Per Second (EPS): The number of security events processed per second.

Understanding these metrics helps you ensure your SIEM system can handle your organisation's data load from day one.

Plan for scalability

As your organisation grows, so will the volume of data and security events. To avoid running into capacity issues later, select a scalable SIEM solution. Consider cloud-based SIEM options that allow you to easily expand storage and processing power without significant manual intervention. Planning for scalability from the beginning ensures your system can handle increasing data without disruptions.

Prioritise integration with existing tools

Your SIEM system should work seamlessly with the tools you already use, such as firewalls, antivirus programs, and Intrusion Detection Systems (IDS). Focusing on integration ensures your SIEM has access to all the critical data it needs to monitor and secure your IT environment. Poor integration can create blind spots in your security monitoring, reducing the effectiveness of your SIEM system.

Focus on training your team

A SIEM system is only as good as the team managing it. Allocate resources to provide comprehensive training to your security personnel. This should include both certifications and ongoing education so that your team stays updated on the latest SIEM tools and best practices. Well-trained staff can fully utilise the SIEM system and respond effectively to threats.

Future trends in SIEM

Here are some key trends that are shaping the future of SIEM, offering more proactive and intelligent solutions for security challenges.

AI and machine learning integration

These technologies automate the process of collecting and analysing data from different sources. Unlike traditional SIEM systems, AI-powered tools can detect threats in real time and respond automatically, reducing the time it takes to stop potential attacks. ML models also learn from past data to recognise patterns that might indicate future threats.

Automated threat response

In the past, an SIEM system would alert your security team when an issue arose, and then they would have to respond manually. Modern systems equipped with AI can take immediate action to stop threats. This means that instead of waiting for a human to intervene, the SIEM system can block suspicious activity, quarantine harmful files, or shut down access to compromised systems instantly.

Integration with emerging technologies

SIEM solutions are also expanding to integrate with other modern technologies, like Internet of Things (IoT) devices, blockchain, and advanced cloud infrastructures. As organisations adopt more digital tools, SIEM systems need to adapt and incorporate data from these sources. This ensures that every part of your digital environment is monitored, providing a comprehensive view of your security operations centre.

Combining SIEM with SOAR

Traditionally, SIEM and SOAR (Security Orchestration, Automation, and Response) systems were separate tools. SIEM handled detection, while SOAR focused on response. However, newer solutions are merging these capabilities into a single platform, creating a more seamless process. This integrated approach enables your SIEM system to not only identify and monitor threats but also respond to them automatically without needing to switch between systems.

Conclusion

Security Information and Event Management play an important role in strengthening your organisation’s security posture. They provide a centralised view of your entire IT environment, allowing your security team to see potential threats that may not be visible through other means. This unified approach helps you catch and mitigate threats that could slip past traditional defences, improving your overall security strategy.

By implementing a robust SIEM platform, such as Tata Communications SIEM, your organisation can not only boost threat detection and response but also reduce costs and improve operational efficiency. Take it from our customer success story with a major financial services firm, who sought a comprehensive solution to address their cybersecurity challenges.

The firm chose Tata Communications SIEM, an on-premise system that leverages industry-leading technology to aggregate every security-related event across the firm’s IT environment, including remote sites and mobile users. The result?

• 1 million Cyber events monitored
• 60 Alarms dealt with
• 300 Devices secured

For more details on Tata Communications SIEM, read the full case study here.