CyberSilo SIEM Integrates with Microsoft Sentinel

Why Unify ThreatHawk and Microsoft Sentinel?

Enterprise security teams across the EU and UK increasingly operate hybrid environments where critical data resides on-premises for residency, latency, or legacy reasons, while cloud-born workloads run on Microsoft Azure. This creates a telemetry divide: on-premises security logs remain siloed, while cloud detection tools miss ground-truth signals from physical infrastructure. Connecting a dedicated EU-hosted SIEM like ThreatHawk with a cloud-native SIEM like Microsoft Sentinel solves this by:

• Centralising correlation — ThreatHawk ingests logs from network devices, servers, endpoints, and OT systems, correlates them locally, and forwards high-fidelity alerts to Sentinel for cloud-side investigation and orchestration.
• Reducing data egress costs — Only processed alerts and enriched metadata leave the on-premises environment, not raw logs, keeping data transfer volumes predictable and compliant with localisation rules.
• Meeting EU regulatory requirements — NIS2 Article 21 mandates proportionate technical and organisational measures for both network and information systems; a unified SIEM view satisfies the requirement for continuous monitoring and incident detection across all critical systems.
• Future-proofing SOC operations — As organisations migrate workloads to Azure in phases, the integration ensures no blind spots emerge during the transition period.

How the Integration Works

The integration follows a publisher-subscriber architecture, with ThreatHawk acting as the event publisher and Microsoft Sentinel as the subscriber. It uses the Azure Log Analytics Data Collector API and Sentinel’s Common Event Format (CEF) parser, ensuring alerts appear as native Sentinel incidents with full context.

Key Benefits for European SOC Teams

Data Sovereignty and Residency Control

ThreatHawk operates from data centres within the EU and UK, allowing organisations to keep raw security logs on sovereign soil. Only alert metadata — stripped of unnecessary PII — is forwarded to Sentinel’s Azure region of choice (West Europe, North Europe, UK South, etc.). This architecture supports compliance with GDPR Article 44–49 on international transfers and with NIS2 Article 23 on supply chain security, as sensitive logs never traverse third-country cloud infrastructure.

Reduced SOC Toil

Without the integration, SOC analysts typically maintain separate dashboards, parsers, and alert triage procedures for on-premises and cloud logs. The ThreatHawk-Sentinel union collapses two monitoring streams into one incident queue, with unified severity scoring and deduplication. This directly reduces alert fatigue — a key concern for SOC managers operating under resource constraints common in mid-sized European enterprises.

Compliance Audit Readiness

Both platforms support long-term log retention and immutable logging for forensic use. ThreatHawk handles on-premises retention (customisable up to 7 years, as required by some EU member state regulations), while Sentinel provides native Azure retention policies. For auditors reviewing NIS2 or DORA compliance, a single query across both environments — via Sentinel’s cross-workspace querying — demonstrates continuous monitoring without gaps.

Use Cases for the Integration

Hybrid Deployment Security Monitoring

Consider a European bank that runs critical payment systems on-premises for regulatory latency requirements while hosting customer-facing web applications in Azure. ThreatHawk monitors the on-premises network segment — including ATM infrastructure, core banking servers, and branch office firewalls — while Sentinel monitors Azure VMs, Azure SQL, and Office 365. The integration correlates a suspicious login from a branch office VPN with a cloud-side privilege escalation attempt in Azure AD, triggering a single incident with complete remediation steps across both domains.

Managed Security Service Provider (MSSP) Scenario

MSSPs serving European clients can deploy ThreatHawk as a tenant-managed SIEM within each client’s on-premises or sovereign cloud environment, then aggregate high-level alerts into a central Microsoft Sentinel workspace for multi-tenant SOC operations. This preserves client data residency while enabling the MSSP to apply AI-driven analytic rules across all clients in one view — a model that aligns with ENISA’s guidelines for managed security services.

DORA Compliance for Financial Entities

DORA requires financial entities to maintain a comprehensive ICT risk management framework, including continuous threat detection and incident reporting. The joint ThreatHawk-Sentinel platform supports DORA Articles 8 (detection) and 9 (response) by providing a single pane of glass for monitoring critical ICT assets, with automated playbooks for incident classification and notification to competent authorities within the mandated timelines.

Comparing Integration Approaches

Organisations evaluating a hybrid SIEM strategy have several architectural options. Understanding the trade-offs — especially for EU data sovereignty — informs the right choice.

For most European enterprises with existing Azure investments, the ThreatHawk-to-Sentinel (CEF) approach delivers the optimal balance of sovereignty, performance, and cost — especially when compared to shipping all raw logs to the cloud.

Best Practices for Deployment

Configuring Data Connectors for EU Data Residency

When setting up the integration, ensure that the Azure Log Analytics workspace used by Microsoft Sentinel is deployed in an EU or UK region (e.g., westeurope, northeurope, uksouth). The ThreatHawk forwarder connector must be configured to use the workspace ID and key corresponding to that region. For organisations requiring separation between production and non-production data, deploy separate workspaces per environment — a practice that also supports NIS2 Article 21’s requirement for proportionate measures based on the asset’s criticality.

Alert Tuning and Noise Reduction

One of the most significant operational gains from the integration is the ability to apply Sentinel’s fusion and machine learning models to ThreatHawk alerts. However, if ThreatHawk is configured to forward all low-severity events, the cloud-side analytic rules will inherit noise. Best practice is to apply a severity threshold in ThreatHawk’s forwarding rules — for example, forwarding only events rated medium severity or higher, plus all security-critical events regardless of severity (such as authentication failures on domain controllers). This keeps Sentinel’s incident queue focused on actionable intelligence.

Retention and Archiving Strategies

ThreatHawk supports configurable retention periods from 90 days to 7 years. For organisations complying with specific EU member state retention laws (e.g., France’s CNIL requirements for 12 months, or Germany’s BDSG guidelines for critical infrastructure operators), ThreatHawk can serve as the long-term archival layer while Sentinel retains data for the analysis window (typically 90 days for interactive queries, with Azure Data Explorer for longer-term cold storage). Configure lifecycle management policies to match your data classification and regulatory needs.

Addressing Common Concerns

Will This Integration Increase Azure Costs?

The integration forwards only alert metadata — typically 1–2 KB per event — rather than raw logs (often 10–100 KB per event). For a 1,000-seat enterprise generating 10 million raw events per day, a traditional log-forwarding approach could cost thousands of euros per month in Azure Log Analytics ingestion fees. With metadata-only forwarding, daily ingestion drops by 90–95%, making the integration cost-neutral or even cost-reducing for enterprises already paying for both SIEMs separately.

Does This Duplicate SIEM Functionality?

No. The two platforms serve complementary roles: ThreatHawk acts as the ground-truth collector for on-premises, OT, and hybrid environments, applying real-time correlation and deduplication locally. Microsoft Sentinel serves as the central nervous system for cloud-side analytics, SOAR playbooks, and cross-platform visibility (Azure AD, Office 365, AWS, GCP). If you forward all events without filtering, you may see some overlap, but the architecture is designed to layer — not duplicate — security operations.

What Happens If Azure Goes Down?

ThreatHawk continues to operate independently on-premises, maintaining full detection and alerting capabilities. The forwarder connector buffers alerts locally (for up to 48 hours by default) when the Azure Log Analytics API is unreachable. Once connectivity resumes, the buffer is drained to Sentinel with time-stamped events, ensuring no data loss. This aligns with NIS2 Article 21’s requirement for business continuity measures and with DORA Article 8’s provisions for ICT system resilience.