What Is SIEM (Security Information and Event Management)?

SIEM — Security Information and Event Management — is a platform that collects, aggregates, and analyzes security log data from all sources in your IT environment: firewalls, Active Directory, email systems, endpoints, cloud platforms, and applications. By correlating events across all these sources in real time, SIEM enables detection of threats that span multiple systems, compliance reporting for auditors, and forensic investigation of security incidents.

How SIEM works

1. Log collection — agents or connectors forward logs from every source to the SIEM: Windows Event Logs, firewall deny/allow records, VPN authentication logs, Microsoft 365 Unified Audit Log, Azure AD sign-in logs, application logs
2. Normalization — SIEM translates logs from different formats into a common schema, enabling cross-source correlation
3. Correlation — rules and machine learning identify sequences of events indicating attack patterns: e.g., failed logins from unusual geography followed by successful login followed by mass file access
4. Alerting — SIEM generates prioritized alerts for security analysts or MDR teams to investigate
5. Reporting — pre-built and custom reports for compliance frameworks (SOC 2, ISO 27001, OSFI B-13), management dashboards, and forensic timelines

SIEM vs. EDR: what's the difference?

• Scope — EDR monitors endpoint processes and file activity; SIEM aggregates logs from every system including network infrastructure, cloud, and applications
• Purpose — EDR is real-time threat detection and response on devices; SIEM is log aggregation, correlation, compliance reporting, and forensic investigation
• Complementary — most enterprise security environments use both: EDR feeds alerts into SIEM, which correlates them with logs from other systems for a complete picture

Leading SIEM platforms in Canada (2026)

• Microsoft Sentinel — cloud-native SIEM built on Azure; strong Microsoft 365 integration; Canadian data residency in Azure Canada Central; pricing based on data ingestion ($2-4/GB/day); most relevant for Microsoft-first Canadian environments
• Splunk — enterprise SIEM with extensive integration ecosystem; higher cost ($150K+/year for enterprise); more common in large enterprises and government
• IBM QRadar — enterprise SIEM; used by Canadian banks and government; complex deployment
• Rapid7 InsightIDR — SMB/mid-market SIEM with MDR add-on; simpler deployment than Splunk or QRadar

When do Canadian businesses need SIEM?

• SOC 2 Type II certification — requires comprehensive log collection and review; SIEM is the standard approach
• OSFI B-13 compliance — federally regulated financial institutions need centralized log management and correlation for incident detection and reporting
• Enterprise customer requirements — many large enterprise clients now require their vendors to have SIEM as part of third-party risk management
• Regulated industries — healthcare organizations under PHIPA, legal firms with large client data volumes, and financial services firms often need SIEM for regulatory compliance
• Post-incident — after experiencing a significant breach, many organizations implement SIEM for forensic capability and to prevent recurrence

Most Canadian SMBs under 200 employees do not need a standalone SIEM — MDR with EDR provides sufficient threat detection. SIEM becomes necessary at mid-market scale or when specific compliance frameworks mandate it.

Related glossary terms

• EDR — Endpoint Detection and Response
• MDR — Managed Detection and Response
• XDR — Extended Detection and Response
• MSSP — Managed Security Service Provider
• OSFI Cybersecurity Guidelines

How Outsource IT Canada can help

• Managed IT Services — 24/7 monitoring and flat-rate IT support for Canadian businesses
• Cybersecurity Services — EDR, MDR, dark web monitoring, and incident response
• PIPEDA Compliance — privacy impact assessments and breach notification procedures
• Get a free assessment — call (416) 623-9677