Can a company truly defend itself against an attack it cannot see?
Modern cybersecurity is based on a paradox: a company can have a high-performance firewall, next-generation antivirus, EDR, backup solution, multi-factor authentication and rigorous security policies… and yet still fail to detect a compromise early enough.
The reason is simple: security tools produce a huge amount of information, but this information often remains scattered.
A server generates logs.
A firewall logs network connections.
An Active Directory retains authentication events.
An EDR monitors the processes executed on the workstations.
Microsoft 365 or Google Workspace record user activities.
Business applications produce their own logs.
Network equipment also has its own logs.
Cloud environments generate yet other events.
Taken individually, each of these elements can provide valuable information. The problem arises when an attack unfolds progressively across multiple systems.
An attacker might, for example:
- compromise a user account
- connect from an unusual IP address
- retrieve information about the environment
- increase his privileges
- access a server
- create an additional account
- disable certain security mechanisms
- exfiltrate data
- deploy ransomware.
No single event necessarily allows us to immediately conclude that an attack has occurred.
It is the correlation between these events that can reveal the scenario.
This is precisely one of the fundamental roles of a SIEM — Security Information and Event Management.
The SIEM therefore constitutes a central layer enabling the collection, normalization, correlation, analysis and exploitation of security events from multiple sources.
NIST defines log management as a process encompassing the generation, transmission, storage, access, and deletion of logs. NIST also emphasizes that this data helps identify and investigate cybersecurity incidents.
SIEM goes beyond simple log storage: it progressively transforms technical events into actionable information for threat detection and response.