How To Guide
How to Use SIEM Tools for Log Management
SIEM aggregates logs to detect threats individual systems miss.
Overview
Brings scattered security events into one correlated view.
Step 1: Choose SIEM
Select platform.
1
Options
- Microsoft Sentinel: Cloud-native
- Wazuh: Free, excellent for SMBs
- Elastic Security: Open source
- Splunk: Enterprise leader
Step 2: Deploy
Set up collection.
1
Sources
- Firewalls and IDS
- Windows security logs
- Domain controller auth
- Email and cloud audit logs
2
Rules
- Failed logins then success
- Unusual location plus data access
- New admin plus elevated access
- Large transfers outside hours
Step 3: Operations
Daily use.
1
Daily
- Review high-severity alerts
- Investigate and document
- Tune for false positives
- Weekly summary reports
3
Create Dashboards
- Executive dashboard: High-level security posture, incident count, risk score
- Security operations: Active alerts, recent incidents, log ingestion status
- Authentication: Failed logins, account lockouts, new accounts, privilege changes
- Network: Traffic patterns, top talkers, blocked connections, IDS alerts
- Compliance: Audit log completeness, policy violations, access reviews
- Customise dashboards for different audiences: IT, management, compliance
4
Threat Hunting with SIEM
- Proactive threat hunting goes beyond waiting for alerts to fire
- Search for: PowerShell encoded commands (often used by attackers)
- Search for: New scheduled tasks or services created on servers
- Search for: Unusual DNS queries (long domain names, high volume to single domain)
- Search for: Lateral movement patterns (RDP, SMB, WMI connections between workstations)
- Search for: Data staging (large archives created in unusual directories)
- Schedule dedicated threat hunting sessions weekly or bi-weekly
5
SIEM Maintenance
- Monitor log ingestion rates — a sudden drop means a source stopped sending logs
- Archive old logs to cheaper storage after the active retention period
- Review and update correlation rules quarterly
- Tune out persistent false positives to keep alert quality high
- Track mean time to detect (MTTD) and mean time to respond (MTTR)
- Conduct quarterly review of SIEM effectiveness with the security team
- Keep the SIEM platform itself patched and updated
Pro Tip:
The value of a SIEM is directly proportional to the quality of your correlation rules and the consistency of your log sources. Missing logs from a critical system can blind you to an active attack.
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