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SIEM (Security Information and Event Management)
Definition
A SIEM is a platform that centralises, correlates and analyses security logs and events from different systems to detect suspicious activities and incidents.
SIEM combines two functions: Security Information Management (SIM), collecting and storing logs, and Security Event Management (SEM), real-time analysis and correlation of events. Modern SIEM platforms use machine learning to detect anomalies.
A SIEM receives data from firewalls, servers, endpoints, cloud services and applications. By correlating events across multiple sources, attack patterns become visible that individual systems cannot detect.
Without a SOC team monitoring the SIEM 24/7, its value is limited. Many organisations therefore opt for an MDR service that combines SIEM functionality with human analysis. Modern SIEM platforms use machine learning and User and Entity Behavior Analytics (UEBA) to detect anomalies based on normal behavioural patterns. This reduces false positives and improves detection of advanced threats. Without specialised expertise, a SIEM can generate more noise than actionable intelligence.
Impact on organisations
The impact on organisations is substantial. Under NIS2, organisations in critical sectors are required to implement appropriate technical and organisational measures. DORA sets comparable requirements for financial institutions. The average cost of a security incident amounts to millions of euros in recovery, legal fees and reputational damage. National cybersecurity centres warn that advanced threat actors increasingly target European organisations.
Protection
Effective protection requires a layered approach combining technical measures with organisational processes and awareness. Regular testing of security measures through pentests and security assessments is essential. An incident response plan with clear roles and communication lines prepares the organisation for worst-case scenarios. Continuous monitoring through an MDR service or internal SOC detects threats before they can cause damage. Security awareness training ensures employees recognise and report suspicious activities.
The threat landscape evolves rapidly. Organisations that operate only reactively face increasing risk. A proactive security strategy combines technical measures with regular security testing, continuous monitoring and a practised incident response team. NIS2 requires organisations in critical sectors to implement demonstrable security measures, including supply chain risk management and regular assessments. The cost of prevention is a fraction of the cost of a security incident: the IBM Cost of Data Breach Report 2024 documents average costs of $4.88 million per incident. Organisations with an MDR service or practised incident response team save an average of $2.66 million per incident compared to organisations without preparation.
How DEFION helps
DEFION offers a comprehensive portfolio of security services that help organisations address this threat. The 24/7 SOC team continuously monitors for suspicious activities. Pentests and red teaming exercises test the effectiveness of existing security measures. In the event of an incident, the DFIR team is immediately available for forensic investigation and recovery. This requires a proactive security strategy that is regularly tested and updated based on the current threat landscape. Organisations that invest in prevention and preparation save significantly on incident response costs. ISO 27001 provides a proven framework for structurally organising information security.