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SIEM 🟢 Protection

A SIEM (Security Information and Event Management), is a cybersecurity software solution who acts as the brains behind an organisation's security.

It collects, standardises and analyses safety data from a variety of sources (event logs, security alertsnetwork data flows, etc.). to detect threats and security incidents in real time.

Illustration SIEM ©ORSYS/Alexandre SALQUE

🎯 SIEM objectives

Threat detection : identify suspicious behaviour (attacks, intrusions, anomalies) using correlation rules, machine learning algorithms and artificial intelligence.
Event correlation : link isolated, seemingly unrelated events to identify complex and sophisticated attack patterns.
Regulatory compliance : generate customisable reports to meet the requirements of standards such as RGPD, ISO 27001PCI-DSS, HIPAA, etc.
Incident response : provide real-time alerts to enable security teams to respond quickly and effectively to incidents.
Analysis forensics : trace post-incident activities by exploiting historical logs to understand the extent of the attack, identify the vulnerabilities and improve safety.

👉 Types of SIEM

On-Premises : deployed locally on the organisation's premises (e.g. IBM QRadar, Splunk). Offers total control, but requires significant maintenance.
Cloud (SaaS) : Hosted and managed by a cloud service provider (e.g. Microsoft Sentinel, Sumo Logic). More flexible and scalable, but can raise security and compliance issues.
Hybrid : combines cloud and local infrastructure. Allows you to benefit from the advantages of both models.
Open source : customisable solutions (e.g. Elastic SIEM, Wazuh). Require in-house technical expertise.
Managed SIEM : outsourced to an MSSP (Managed Security Service Provider). Ideal for companies with limited resources.

How it works

Collection : retrieves logs and events from all sources (firewallIDS/IPS, servers, applications, etc.).
Standardisation : structures data in a common format to facilitate analysis and correlation.
Analysis: applies rules, machine learning or AI to detect threats and anomalies.
Correlation : identifies the links between events to reconstruct the sequence of attacks.
Alert and response : notifies security teams and triggers automated actions (e.g. IP blocking, system isolation).
Reporting : generates dashboards and reports for compliance, audit and trend analysis.

✔ Benefits

Centralisation : unified view of security threats and events.
Proactive detection : reduction in response time (MTTD/MTTR) and minimisation of the impact of attacks.
Compliance : automation of regulatory reporting and simplification of audits.
Automation : integration with a SOAR (Security Orchestration, Automation, and Response) to automate incident response.
Scalability : suitable for large infrastructures and high data volumes

✖ Disadvantages

Complexity : demanding configuration and maintenance, requiring safety expertise.
High costs : licences, log storage, expertise required, especially for on-premises solutions.
False positives : irrelevant alerts if the rules are poorly configured, which can overwhelm security teams.
Latency : processing times for very large volumes of data, which can have an impact on real-time detection.
Log dependency : requires full instrumentation of systems for optimum visibility.

💰 Costs

Licences : from a few thousand to hundreds of thousands of euros a year, depending on the size of the company and the features involved.
Infrastructure : dedicated servers, storage, bandwidth (cost varies according to volume of logs and type of deployment).
Maintenance : in-house or outsourced teams (MSSP).
Training: team certification (e.g. Splunk, ArcSight).

📈 Trends 2025

IA/ML : improved threat detection zero-day and abnormal behaviour thanks to machine learning and artificial intelligence.
SOAR-SIEM convergence : Increased automation of incident response thanks to close integration between SIEM and SOAR solutions.
Cloud-based SIEM : massive adoption of SaaS solutions for greater flexibility, scalability and cost reduction.
Zero Trust : integration with Zero Trust architectures to strengthen access and data security.
XDR (Extended Detection and Response) : merging SIEM capabilities with solutions EDR (Endpoint Detection and Response) for comprehensive protection against threats.

Examples of SIEM solutions

Splunk Enterprise Security
Microsoft Sentinel
IBM QRadar
LogRhythm
Elastic SIEM
Fortinet FortiSIEM
Rapid7 InsightIDR
Exabeam

📊 Key figures (2023-2024)

World :

Global SIEM market : 6.4 billion in 2023, with a projection of $12.7 billion by 2028 (Source: Gartner).
Adoption of the SIEM : 60 % of companies use a SIEM to respond to attacks from ransomware (Source: Gartner).
Violation detection time : 207 days in average without SIEMagainst less than 50 days with a SIEM.

France :