🛠️ What is SIEM?
SIEM is a platform that collects, aggregates, and analyzes security data from across an organization’s digital environment.
🔍 Core Functions of a SIEM:
- Log Aggregation: Collects logs from firewalls, servers, applications, and endpoints.
- Event Correlation: Connects related events across multiple sources.
- Alerting: Triggers alerts when suspicious patterns are detected.
- Visualization: Offers dashboards for monitoring and investigation.
- Forensics Support: Helps during incident investigations.
📋 Common SIEM Tools
| Tool | Description |
|---|---|
| 🔷 Splunk | Enterprise-grade SIEM with powerful analytics and ML. |
| ⚙️ ELK Stack | Open-source suite (Elasticsearch, Logstash, Kibana). |
| 🧠 IBM QRadar | Used by large enterprises; strong correlation engine. |
| 🧰 Graylog | Lightweight and user-friendly; perfect for learning. |
Each of these platforms helps SOC Analysts turn raw log data into actionable insights.
📂 What is Log Analysis?
Log Analysis is the process of reviewing system-generated log entries to detect anomalies, attacks, or errors. It’s a critical part of incident detection and response.
🗂️ Typical Log Sources:
- 🔐 Firewall Logs
- 🧱 IDS/IPS Logs
- 💻 Windows Event Logs
- 🐧 Linux Syslogs
- 🌐 Web Server Logs (e.g., Apache, Nginx)
- 👥 Authentication & Login Logs
🧑💻 How SOC Analysts Use SIEM for Log Analysis
SOC Analysts interact with SIEM platforms to:
- 📈 Monitor systems in real-time
- 🔎 Search logs using queries (e.g., Splunk SPL, Kibana KQL)
- 🧩 Correlate events to find attack patterns
- 🧪 Investigate incidents with supporting evidence
- 🧠 Improve detection rules based on findings
🧪 Sample Query (Splunk)
index=windows sourcetype=WinEventLog:Security EventCode=4625
| stats count by Account_Name, host, _time
| where count > 5
🔍 This Splunk SPL query finds failed login attempts (EventCode 4625) grouped by user and host, flagging accounts with more than 5 failures — a common sign of brute-force attacks.
✅ Summary ✅ SIEM provides the intelligence. ✅ Logs provide the evidence. ✅ You, the SOC Analyst, provide the expertise.
Mastering SIEM and log analysis is a foundational skill for any SOC Analyst. By understanding what’s happening across your systems, you can detect threats faster, respond more effectively, and protect your organization from cyber attacks.
🚀 What’s Next? In the next article, we’ll explore real-world log examples and show how to investigate potential attacks using SIEM tools.
Stay tuned, blue teamer! 🧢🛡️