SIEM as a Service differs little from other cloud-based SaaS solutions: your entire SIEM architecture exists on a remote server, which you can access through a dashboard. This makes it highly scalable. However, it doesn’t include oversight of a human security team. Sometimes this is all a smaller business needs, but as organizations grow, they may need more hands-on expertise
Benefits of SIEM as a Service
Elastic scaling and automatic updates: Cloud-hosted SIEM platforms update and scale on demand.
Lower upfront costs: You don’t need to purchase or maintain hardware.
Automatic maintenance: System updates and patches are handled by the provider.
Trade-offs with SIEM as a Service
Data residency and compliance implications: With multi-region storage, many countries restrict certain data from being transferred or handled in another country, or even off-premises. The more important your data is, the more you’ll run into these types of restrictions.
API-driven integrations vs. on-prem log sources and bridge strategies: Traditional data logging techniques work best in-house. SIEM as a Service demands API-based logging, as the server processing your SIEM work is remote. If you already operate in a multi-cloud environment, this should be no problem, but if you maintain exclusively in-house servers, you'll have to adapt your approach.
Shared responsibility model: Cloud providers manage the host OS, virtualization layer, and physical infrastructure. You’re responsible for the guest OS, application layer, firewall configurations, and other in-house controls. Unfortunately, this can create responsibility gaps if not managed properly.