DefinitionSIEM (Security Information and Event Management) is a platform that collects, centralizes and correlates logs and events from many IT sources to detect suspicious activity, raise alerts, support investigations and keep records for audit and compliance.
How it works
A SIEM receives events from firewalls, servers, endpoints, applications, cloud services and identity systems. It then:
- Normalizes the data, so events from different vendors can be compared.
- Correlates events through rules and analytics, for example: several failed logins followed by a successful access from an unusual country.
- Raises prioritized alerts for analysts.
- Retains and indexes records, enabling searches during investigations and evidence for audits.
Many SIEMs include user and entity behavior analytics (UEBA) and integrate with automation tools (SOAR).
SIEM is not a SOC
A SIEM is a tool; on its own, it protects no one. Without analysts following alerts 24/7, rules tuned to the environment and a response process, it becomes a repository of alerts nobody reads in time. Its value appears when it is operated by a SOC, with detection coverage mapped, for example, to MITRE ATT&CK.
SIEM vs XDR
SIEM is broad: it accepts logs from almost any source and is strong in retention and compliance, but it requires continuous rule engineering. XDR focuses on detection and response, with ready-made cross-layer correlation. Many operations use both in a complementary way. When choosing, weigh cost per volume of ingested data, coverage of critical sources and the retention period required by standards and regulators.
Network Secure operates SIEM as part of its 24/7 SOC.
Frequently asked questions
Is having a SIEM the same as having a SOC?
No. A SIEM collects and correlates events; the SOC is the team and processes that analyze alerts and respond to incidents.
What is the difference between SIEM and SOAR?
SIEM detects threats and raises alerts from logs. SOAR automates and orchestrates the response actions to those alerts through playbooks.