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.

Overview

Step 1: Choose SIEM

Options

Step 2: Deploy

Sources

Rules

Step 3: Operations

Daily

Create Dashboards

Threat Hunting with SIEM

SIEM Maintenance

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