Syslog
Source inside Syslog

OpenVPN (Syslog)

OpenVPN server connection and authentication events

Recommendation

High-value events at high volume detected through aggregation or jobs, or high-value context used mainly in investigations.

Retention is set per table, so the retention for this source is advisory.

How the matrix works

C2 Authentication and credential use

Authentication and credential use, including non-interactive, service principal, managed identity, federated, VPN, NAC, and password vault access

T3 High-volume aggregation

Primary, high or very-high volume, and the generic detection use is aggregation, threat-intelligence matching, baselining, or investigation.

Rows that belong to this source

ProcessName =~ "openvpn"

Rules query these rows through the OpenVpnEvent parser.

Sources for this recommendation

  • Azure-Sentinel public content corpus Table identity and usage evidence from public analytics rules, hunting queries, parsers, and solution content. Classification, tier, retention, and billing recommendations require human review.
  • Log Baseline classification rules Value rules C1-C9 mapped to ASD and CISA guidance, and tier rules T1-T5 including plan support. Stored per table as valueRule and tierRule.
  • Log Baseline volume model Judgment-based volume driver and relative volume class per table. Not measured tenant volume.
  • ASD ACSC Priority logs for SIEM ingestion: Practitioner guidance Loosely prioritized log categories (EDR, network devices, domain controllers, Windows, virtualisation, cloud, containers, databases, MDM, DNS, Linux, macOS) used by the classification rules. Collection priority, not storage tier.
  • CISA Guidance for Implementing M-21-31 Prioritized event types for collection and storage (ICAM, operating systems, network infrastructure, cloud, AWS, Azure, Microsoft 365, GCP) used by the classification rules. Collection priority, not storage tier.