# What is SIEM (Security Information and Event Management)?

> SIEM is a security platform that aggregates logs and events across an organization, correlates them to detect threats, and supports investigation, alerting, and compliance reporting.

Source: https://openobserve.ai/glossary/what-is-siem/
Published: 2026-07-08
Term: SIEM
Category: Security
Related terms: what-is-log-management, what-is-log-aggregation, what-is-telemetry-pipeline

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**SIEM (Security Information and Event Management)** is the security team's central nervous system: a platform that aggregates security-relevant logs and events from across an organization - endpoints, servers, cloud accounts, identity providers, firewalls, applications - correlates them to detect threats, and provides the search, alerting, and reporting that investigations and compliance require.

## What a SIEM does

- **Collection & normalization** - ingest logs from hundreds of sources and map them onto a common event schema
- **Correlation & detection** - rules and analytics that turn raw events into alerts: impossible-travel logins, privilege escalation chains, data exfiltration patterns
- **Investigation** - fast search across months of history to reconstruct what an attacker did
- **Case management & response** - triage, assignment, and (with SOAR integration) automated playbooks
- **Compliance** - retention and reporting for PCI DSS, HIPAA, SOC 2, ISO 27001

## SIEM's economics problem

Security telemetry is the highest-volume, longest-retention data in the company - cloud audit trails and authentication logs alone can dwarf application logs, and compliance regimes demand months-to-years of retention. Traditional per-GB-per-day SIEM pricing forces the worst possible trade-off: **filtering out the data you might need for the investigation you haven't had yet.** This is why modern security architectures separate the storage layer (cheap, complete, object-storage-based) from the detection layer.

## SIEM and observability convergence

The raw material of SIEM is the same as observability: logs, events, [aggregation pipelines](/glossary/what-is-log-aggregation/). Teams increasingly route security telemetry - [Okta events](/blog/analyze-okta-events-for-better-security-and-observability/), [Falco runtime alerts](/blog/how-to-setup-falco-on-kubernetes/), VPC flow logs, WAF and CloudTrail logs - into their observability platform, gaining one query surface and one retention policy for both operational and security data.

## Security analytics with OpenObserve

OpenObserve serves as a high-volume, low-cost security log backend: object-storage retention makes keeping *everything* affordable, [pipelines](/pipelines/) handle normalization and [PII redaction](/blog/redact-sensitive-data-in-logs/) in flight, and SQL-based alerting powers detection rules across sources - the SIEM data layer without SIEM data pricing.