SIEM tools: a practical buyer's guide
SIEM (security information and event management) tools collect logs from your systems, correlate them and alert on threats. Well-known options include Microsoft Sentinel, Splunk Enterprise Security, Google Security Operations, Elastic Security and the open-source Wazuh. The tool is only half the cost: someone has to write detections, triage alerts and respond, around the clock.
What a SIEM does
- Collects logs from identity providers, cloud accounts, firewalls, endpoints and SaaS apps.
- Normalises them so events from different sources can be searched together.
- Runs detection rules and correlation to raise alerts.
- Keeps logs for investigation and compliance (ISO 27001, SOC 2, PCI DSS).
Types of SIEM tool
- Cloud-native SIEM: hosted by the vendor and priced by data volume. Examples: Microsoft Sentinel, Google Security Operations.
- Traditional or self-managed SIEM: deployed and scaled by you. Example: Splunk Enterprise Security on your own infrastructure.
- Open source: free software, paid for in engineering time. Examples: Wazuh, Elastic.
How to choose a SIEM tool
- Integrations for the systems you actually use, maintained by the vendor.
- Pricing model: per GB ingested can grow fast. Model a year of real log volume.
- Detection content included out of the box, and how it is kept current.
- Who will watch it: alerts at night and weekends need a team or a service.
When a SIEM is not the right first step
Smaller teams often buy a SIEM and then drown in alerts nobody has time to triage. Vigilbase OS takes a different approach: it connects to your existing tools, investigates alerts with AI, and brings only verified threats to your team with the evidence and the approved fix. It gives you security operations without hiring a SOC.
Frequently asked questions
What is the difference between SIEM and SOAR?
A SIEM collects data and raises alerts. SOAR (security orchestration, automation and response) runs playbooks that act on those alerts. Many platforms now combine both.
Do small businesses need a SIEM?
They need the outcome: someone notices and stops attacks. A full SIEM is often more than a small team can run, so managed or AI-driven security operations is usually a better fit.
Are there free SIEM tools?
Yes. Wazuh and the free tier of Elastic are common. The software is free, but deploying, tuning and watching it takes significant time.