OpenSearch Security Analytics: open source SIEM with Sigma rules

OpenSearch Security Analytics plugin, released with OpenSearch 2.4 (15 November 2022): detectors for network, cloud, endpoint, native Sigma rule support, correlation engine added in 2.7. Apache 2.0 licence.

Cyber SecurityOpen Source OpenSearchSIEMSecurity AnalyticsSigmaCyber SecurityOpen Source

The OpenSearch fork

After Elastic’s licence change in January 2021, Amazon Web Services announces the OpenSearch fork, based on the last Apache 2.0 versions of Elasticsearch 7.10 and Kibana 7.10. The first stable release OpenSearch 1.0 is dated 12 July 2021, under Apache 2.0 and governed by a community foundation (from 2024 the OpenSearch Software Foundation under Linux Foundation).

The fork inherits many features from Open Distro for Elasticsearch and adds new plugins developed by the community and AWS.

Security Analytics plugin

On 15 November 2022 OpenSearch 2.4 was released, introducing the Security Analytics plugin: a native SIEM solution for OpenSearch with a detection-as-code approach.

Initial version features:

  • Detectors — logical entities ingesting logs from a specific domain (network, DNS, Windows, Linux, AD, AWS CloudTrail, Azure, GCP, GitHub)
  • Sigma rules — native support for the Sigma format, open standard for SIEM rules
  • Findings — rule results with context, severity and timestamp
  • Alerts — finding escalation through the Alerting plugin
  • Rule editor — rule creation and editing via OpenSearch Dashboards UI

Correlation engine (OpenSearch 2.7)

In May 2023, with OpenSearch 2.7, a correlation engine was added, enabling:

  • Correlation rules — links between findings across different detectors
  • Threat intelligence feed — integration with STIX/TAXII and commercial feeds
  • Finding graph — visualisation of relationships between events
  • Campaign detection — aggregation of related findings

Licence and governance

  • OpenSearchApache 2.0 (OSI-approved)
  • Security Analytics plugin — Apache 2.0
  • Governance — from September 2024 under OpenSearch Software Foundation, part of Linux Foundation, with corporate contributors (AWS, Uber, SAP, Canonical, Aiven, ByteDance, Oracle, Atlassian)

This approach removes the licensing concerns affecting Elasticsearch post-2021.

Sigma integration

Sigma is a YAML standard for SIEM rules agnostic of the backend. Security Analytics can import Sigma rules and translate them into OpenSearch queries. The Sigma project publishes community rules (github.com/SigmaHQ/sigma) covering MITRE ATT&CK techniques for Windows, Linux, network, cloud.

This makes OpenSearch Security Analytics interoperable with the modern detection engineering ecosystem.

Adoption

  • Cloud providers — AWS OpenSearch Service with Security Analytics preconfigured
  • Companies with OSI licence constraints — alternative to Elastic Security
  • European operators — scenarios with data sovereignty and self-hosted SIEM
  • Integration with existing OpenSearch — security extension of clusters already in use for logs and observability

In the Italian context

OpenSearch Security Analytics is chosen by public administration, telcos, MSSPs preferring OSI-approved licences and wanting SIEM on self-hosted or sovereign cloud infrastructure. Availability of community Sigma rules reduces initial detection engineering effort, leaving room for context-specific tuning.


References: OpenSearch Security Analytics (OpenSearch 2.4, 15 November 2022). Correlation engine (OpenSearch 2.7, May 2023). OpenSearch fork started by AWS on 12 April 2021; OpenSearch 1.0 released 12 July 2021. Apache 2.0 licence. Governance: OpenSearch Software Foundation (Linux Foundation, 2024). Website: https://opensearch.org

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