Security Onion
Source-available (ELv2) network security monitoring on Suricata, Zeek, and the Elastic Stack. Self-hostable and airgappable; SSO and disk encryption require the paid Pro tier.
Compliance
Category: Compliance under Security & Privacy
Wazuh
GPL-2.0 unified XDR and SIEM platform from Wazuh, Inc. All capabilities including RBAC, threat hunting, and compliance mapping modules included in the open-source binary; paid tier is managed cloud only.