Case Study : Taming the 21,000-Alert-a-Day SIEM

🚨 The Problem

The client’s SOC was drowning in noise.

Their Splunk Enterprise Security environment was generating over 21,000 notable events every single day. Analysts were overwhelmed, alert fatigue had set in, and confidence in the platform was fading fast.

🔍 My Role

I was brought in as a specialist consultant to run a full health check of their detection environment and design a recovery path that actually stuck.

✅ What I Did

1. Full Detection Health Check

• Analysed detection rules, notable volumes, data sources, and KPIs
• Audited CIM and data model acceleration
• Identified root causes of alert bloat and duplication

2. Prioritised Fixes

• Delivered quick wins (rule tuning, macro simplification)
• Proposed a phased roadmap that worked for both SOC and engineering teams

3. CIM & Data Model Repairs

• Normalised key log sources
• Improved CIM compliance
• Fixed broken acceleration and tagging to boost correlation speed and accuracy

4. Detection Overhaul

• Re-wrote 220+ correlation rules
• Removed duplication, added severity logic, restructured macros
• Reduced ES search time by over 60%

📉 The Results

• Alert volume dropped by 99%
• False positives significantly reduced
• Analysts re-engaged with detection workflows
• Detection engineering became maintainable again
• Stakeholders finally trusted the data

🔧 Tools & Tactics Used

Splunk ES · CIM · Data Models · Custom Macros · Detection Frameworks · Stakeholder Workshops

🤝 Want Results Like This?

If your detection pipeline is out of control — or if your team is burned out on bad alerts — I can help.

📬 Get in touch — or explore more of my work.