“You can collect all the logs in the world, but if you can’t detect, you’re just archiving risk.”
Modern SIEMs aren’t just log aggregators—they are the analytical backbone of security operations. But to unlock their value, you need more than ingestion and alerts. You need detection-first thinking.
This post outlines the real strategy behind detection-first SIEM design: rule engineering, cross-correlation, anomaly detection, dashboarding, and threat-informed use cases. Whether you use Splunk, Microsoft Sentinel, Elastic, or Chronicle, the principles apply.
Detection Rule Types: Architecting for Context
Scheduled Rules
Run periodically using structured queries. These are the foundation of most SIEMs. Ideal for repeatable patterns like brute force, failed logins, suspicious parent-child process chains.
Example: In Splunk, a scheduled correlation search using Windows logs (4688 + 4689) to detect suspicious PowerShell spawn chains.
Near-Real-Time (NRT) / Streaming Rules
Triggered upon data arrival, designed for speed. Best for critical changes: privilege escalation, unusual access, high-risk alerts from endpoint tools.
Chronicle supports streaming detections using its UDM model. Splunk can use real-time alerts for similar cases.
Anomaly-Based Rules
Don’t rely on UEBA buzzwords. True anomaly detection starts with profiling your own normal.
In Splunk: build a dashboard showing average daily network traffic per asset over 30 days. Alert when current volume exceeds 3x the baseline.
In Sentinel: use KQL to compare a user’s authentication patterns this week vs. the last 30 days.
This isn’t AI—it’s behavioral profiling using data you already have.
Cross-Correlation Rules
The real depth of detection. Combine multiple telemetry sources to tell a story.
Example: DNS request to known C2 domain + unusual PowerShell command + rare parent process = likely beaconing behavior.
Requires good normalization (CIM, ASIM, UDM) and thoughtful data modeling.
Threat Intel & Fusion Rules
Auto-match IOCs or build multi-stage correlations. Sentinel’s Fusion, Splunk’s TIF, and Chronicle’s TI integrations play here. Good for:
- Surfacing active attacker infrastructure
- Grouping alerts into incidents
Dashboards: Visibility Is Architecture
Dashboards aren’t decoration—they are operational control surfaces.
What should a good dashboard show?
- Alert volume trends by rule type and severity
- MITRE ATT&CK heatmaps by data source or tactic
- Log pipeline health (ingestion gaps, parser errors)
- Threat intel hits by type, asset, geography
- SOC KPIs: MTTR, MTTD, true positive rates
SIEM Platform Comparison
| Feature | Splunk | Sentinel | Elastic | Chronicle |
|---|---|---|---|---|
| Custom Dashboards | ⭐⭐⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐ |
| MITRE Visualizations | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐ |
| Threat Intel Views | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐⭐ |
| Flexibility & Drilldowns | ⭐⭐⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐ |
Splunk is still the most powerful for dashboarding—but it demands SPL skills and governance.
Threat-Informed Detection Engineering
Your use cases should not be built from guesswork. They should come from:
- MITRE ATT&CK mappings
- Threat intel reports
- Purple teaming & emulation outcomes
- Real attack chains
Don’t alert on “rare command” — detect T1059.001 in the context of a real user and a real sequence.
Build rules that reflect how attackers think, not just how logs behave.
Threat Hunting: Proactive Intelligence, Not Passive Alerting
Threat hunting is hypothesis-driven exploration:
- What doesn’t look right?
- What shouldn’t be here today?
Every hunt can result in:
- New dashboards
- New detections
- Enriched context for triage
Use the SIEM to test ideas, not just to react. Good hunters generate reusable knowledge.
Final Word
Your SIEM is not your strategy. Your detection logic is.
- Design rules that reflect reality
- Build dashboards that expose gaps
- Hunt for signals before they become alerts
- Use threat intel to shape—not drown—your visibility
If you’re not intentional, you’re just logging.
Detection-first SIEM isn’t a product feature. It’s an engineering mindset.
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