Security information and event management (SIEM) is a cybersecurity solution that collects, analyses, and correlates security data from various sources to detect, investigate, and respond to potential threats in real time.
Table of Contents
SIEM Meaning
A security operations centre (SOC) plays an increasingly important role in cybersecurity. A SOC is a centralised unit that handles security issues within an organisation. It is an essential part of a comprehensive cybersecurity strategy, designed to monitor, detect, respond to, and mitigate cyber threats in real time. The volume and sophistication of cyberattacks have made SOCs indispensable for organisations aiming to protect their digital assets and maintain robust security postures.
SIEM Security Functions
SIEM systems operate by collecting and aggregating log data, performing correlation analysis to identify anomalies, and generating actionable alerts for security teams. They also provide detailed reports to help with compliance and auditing requirements. As a cornerstone of modern security operations centres (SOCs), SIEM enhances threat detection, incident response, and overall security posture by transforming raw log data into actionable intelligence to ensure organisations can proactively mitigate risks.
Log collection
SIEM systems gather log and alert data from various devices and applications across the IT infrastructure, including firewalls, servers, endpoints, databases, and cloud services. This aggregation ensures that all security-relevant information is stored in one place, streamlining visibility and eliminating silos. Logs can include user activity, system errors, access attempts, and application-specific events. The ability to ingest data from diverse sources enables SIEM to provide a holistic view of an organisation’s security landscape.
Correlate security events
Correlating security events involves analysing patterns and relationships between multiple logs to identify potential threats or suspicious behaviors. For example, a single failed login attempt might not trigger concern, but multiple failed attempts followed by a successful login from an unusual location could indicate a brute force attack. By applying predefined rules, machine learning algorithms, and context-aware analysis, SIEM identifies these patterns and prioritises potential security incidents for investigation.
Alerts and notifications
When anomalous activity or a potential security incident is detected, SIEM systems generate alerts based on pre-defined thresholds and rules. These alerts are sent to security teams via dashboards, emails, or integrated response tools. For instance, an alert might be triggered for unauthorised access to a critical database or abnormal traffic spikes indicative of a denial-of-service (DoS) attack. Alerts are prioritised to help security personnel focus on the most critical issues first, improving response efficiency.
Report generation
SIEM platforms generate comprehensive reports that summarise security events, trends, and incident responses. These reports are essential for understanding the organisation's security posture over time, meeting compliance requirements, and providing actionable insights to improve future defences. They can also include workflows for incident management, detailing step-by-step procedures for containment, eradication, and recovery after a breach. Reports often serve as critical documentation for internal reviews and external audits.
SIEM tools
SIEM tools collect and analyse large volumes of data from organisation's endpoints in real-time, and detect and block cyber threats by working alongside security teams. You need to define rules to help those teams and generate alerts.
SIEM tools also help with:
- Event logs that can help consolidate data from numerous sources.
- Adding intelligence to raw data obtained from a correlation of events from different logs or sources.
- Automation of security alerts. Most SIEM platforms will allow you to set up direct notifications.
SIEM and security orchestration, automation, and response (SOAR) tools have been instrumental in centralising security event data and automating response workflows. Despite their utility, they face significant challenges:
- Data overload: SIEM platforms often generate excessive alerts, overwhelming SOC teams and leading to alert fatigue.
- Integration complexity: SOAR relies heavily on seamless integration with various tools, which can be complex and time-consuming.
- Operational silos: Both technologies require substantial manual effort to correlate data and orchestrate responses, creating inefficiencies in incident response.
While these tools remain valuable, their fragmented approach to detection and response has created an opportunity for XDR to provide a more cohesive solution.
XDR vs. SIEM
XDR is similar to SIEM, in that it is a tool to improve security level and efficiency. The differences between SIEM and XDR are as follows:
Data collection targets and contextualisation
- SIEM: Collects, manages, and analyses events and logs generated within a network or system. Analysis is performed primarily on log data to detect abnormal activity and signs of attacks.
- XDR: Collects and analyses telemetry data from multiple data sources, including endpoints, networks, and the cloud. It collects not only security events, but also endpoint file and process information, network traffic data, etc.
Analysis and detection
- SIEM: Analyses the collected data according to predefined rules and algorithms. It detects unusual activity or signs of attacks and generates appropriate alerts and warnings. Some products have the ability to perform correlation analysis between mechanical logs. However, the judgment of whether or not an event is a possible cyberattack relies on the "human intuition" of the operator.
- XDR: Based on the threat intelligence (malware, malicious sites, malicious emails, attack methods used by cyber attackers, etc.) possessed by cybersecurity companies that provide XDR, signs of cyberattacks are determined for the collected telemetry.
Incident response and automation
- SIEM: Provides basic information and procedures for security incidents to assist in incident response; SIEM is primarily focused on alert generation and monitoring, while other products may be required for actual response procedures.
- XDR: Provides automation and orchestration capabilities to support rapid response to security incidents. Detected threats are analysed and response guidance is provided in real time.
Dependence on the source
- The value of a SIEM solution is directly related to the sources from which it obtains its information. If there are gaps in the coverage, they are often noticed late or not at all.
- In consequence, if we compare SIEM to XDR, we should also point out that in most cases it is not an either/or decision. More often it is XDR and SIEM, since SIEMs get most value from detection and response logs.
- Due to the dependence of a SIEM solution on the quality of information generated by third-party providers, it often happens that both variants are used in parallel and XDR solutions pass the pre-correlated data on to the SIEM.
SIEM benefits
Logs can be managed centrally
By introducing SIEM, logs can be managed centrally. This eliminates the need to manage logs for each device and reduces management errors and omissions. In addition, SIEM has the function of normalising collected logs and visualises the entire IT environment, enabling efficient and comprehensive management.
Early detection of security incidents and threats
SIEM centralises log management and performs correlation analysis in real time, enabling early detection of incidents and threats. When a threat symptom or incident is discovered, a quick response can be made and the spread of damage can be minimised.
Preventing internal fraud
Security incidents are not only caused by external cyberattacks. Preventing misconduct by employees of your own organisation is also an important security measure for an organisation. By introducing SIEM, you can detect suspicious employee behavior and unauthorised access. SIEM is also effective in preventing internal fraud.
Eliminating the shortage of security personnel
By using SIEM, you can streamline security operations. By automating a series of tasks such as log aggregation, normalisation, and analysis, you can reduce the resources required for your organisation's security measures. Although a certain level of security knowledge is required to operate SIEM, introducing it will enable you to implement more efficient security measures than before.
The role of SIEM in SOC
SIEM is primarily used in a security operations centre (SOC), an organisation that monitors security within an organisation and understands the occurrence of cyberattacks and incidents. It is an important tool for security professionals to support efficient security operations in the following ways.
Alert notification through integrated log management
SIEMs manage various logs in an integrated manner and detect signs of abnormal activity or attacks, and alert security personnel. For example, in addition to detecting malware and other unauthorised behavior, SIEM will alert you when suspicious events are detected, such as multiple login attempts to servers where critical information is stored or use of cloud services not authorised by your company.
Incident investigation and response
Based on unauthorised or suspicious events, SIEM investigates whether or not it is a cyberattack (normal behavior, access error, etc.). If determined to be a cyberattack, the route and scope of the attack, including whether it is an external or internal cyberattack, can be traced to provide clues for incident response.
Reporting
From a medium- to long-term perspective, visualise the status of violations of your company's security policies and the impact of cyberattacks, then create a report. By visualising what kind of cyberattacks the company has been subjected to over a period of one month, three months, six months, one year, etc., the company can consider what security measures it should take next.
The main use cases of SIEM are listed above, but the greatest benefit for security personnel is the ability to quickly visualise events and log information from multiple different products and link them to the next action.
SIEM challenges
While SIEM brings benefits to SOCs and other organisations, it also presents the following challenges:
Complex implementation and configuration
SIEMs are complex systems that require time and expertise to implement and configure. Security professionals must continually work to integrate device logs and data sources, configure rules, and tune alerts.
Processing large amounts of log data
A large amount of log data must be processed and analysed. Appropriate hardware and storage resources are needed to process large amounts of data. It is also necessary to manage log data retention periods and data compression/reduction.
Ongoing response to false positives and alert overload
SIEMs generate alerts based on predefined rules and patterns, however; false positives and negatives can occur. Depending on the configuration, a large number of alerts may be received, requiring continuous tuning of alerts and improvement of rules on the user side.
Response after incident detection
When an event is detected in real time, the actual incident must be confirmed and responded to. If security personnel does not tune up alerts ahead of time, they will be required to respond to alerts of various sizes, which may in turn reduce operational efficiency.
Skill and resource requirements
Proper implementation and operation of SIEM requires security analysis and log management skills. It also requires the availability of appropriate resources (personnel, hardware, and software).
Where can I get help with SIEM?
As you’ve read, SIEM isn’t something that should be done in isolation. Trend Vision One™ Security Operations (SecOps) correlate events across endpoint, server, email, identity, mobile, data, cloud workload, OT, network, global threat intelligence feeds – integrating XDR, agentic SIEM, and SOAR for comprehensive context.
SecOps help you surface the highest priority, gain actionable alerts, and automate complex response actions. Your teams spend less time on tedious, repetitive tasks, and more time on high value, proactive security work like threat hunting and detection engineering.
Joe Lee is Vice President of Product Management at Trend Micro, where he leads global strategy and product development for enterprise email and network security solutions. Joe brings over 30 years of experience in IT and cybersecurity, with a career that spans infrastructure design, datacenter operations, and security leadership. His earlier roles—ranging from building IT departments from the ground up in Europe and Japan to leading Security Operations Centers in Taiwan and the Philippines—have given him a deep, hands-on understanding of enterprise challenges.
This foundation fuels his ability to craft innovative, scalable solutions that align with real-world needs. Joe is known for his strategic vision, mentorship of global product teams, and ability to drive cross-functional collaboration to deliver market-leading security products
Frequently Asked Questions (FAQ's)
What does security information and event management do?
Security information and event management (SIEM) collects, analyses, and correlates security data from across an organisation’s IT systems to detect threats, support incident response, and ensure compliance.
What are the three main roles of a SIEM?
The three main roles of SIEM are to collect and centralise security data, detect and alert on potential threats, and support incident response and compliance reporting.
What is the purpose of a security information and event management correlation rule?
The purpose of the security information and event management (SIEM) correlation rule is to catch complex cybersecurity threats that other threat detection methods might miss.
What is the difference between security information management and security event management?
Security information management (SIM) collects and analyses long-term log data for compliance and reporting. Security event management (SEM) focuses on detecting and responding to threats quickly.
What is an example of a SIEM tool?
Examples of tools commonly used in security information and event management (SIEM) include data collecting tools, search nodes, index and aggregation points, and security alerts.
What are the three types of SIEM?
The three main types of security information and event management (SIEM) systems are on-premises (on-site) SIEM, cloud-based SIEM, and hybrid SIEM models.
What is considered a SIEM?
Security information and event management (SIEM) is any cybersecurity service or solution that analyses IT logs to detect and respond to possible cybersecurity incidents.
What is the difference between a firewall and a SIEM?
A firewall blocks malicious attacks from infiltrating IT systems. Security information and event management (SIEM) is a broader solution that detects cyberthreats inside a system.
What is a SIEM software?
Security information and event management (SIEM) software is a cybersecurity tool that analyses data from IT logs to detect, and respond to cyber threats.
What is the difference between SIEM and SOC?
Security operations centres (SOCs) are teams of cybersecurity experts. Security information and event management (SIEM) is a tool SOCs use to detect and prevent cyberattacks.