Security information and event management systems promise comprehensive visibility into security events across your entire infrastructure. Reality proves more complicated. Many organisations deploy SIEM solutions that generate overwhelming alert volumes while missing actual attacks.
Log collection forms the foundation of effective SIEM implementation. Systems must send logs somewhere before anyone can analyse them. Yet many critical systems either don’t log important security events or never forward their logs to the SIEM.
Windows event logs contain valuable security information, but the default capture is insufficient in detail. Enabling advanced audit policies generates the events needed to detect attacks. Without proper configuration, your SIEM can’t alert on what it never receives.
Network devices rarely send security-relevant logs by default. Firewalls, switches, and routers all handle sensitive traffic, but their logs often focus on operational issues rather than security events. Custom logging configuration captures the information security teams need. When you request a penetration test quote for security monitoring validation, you’re ensuring your SIEM would actually detect real attacks.
Application logs vary wildly in quality and format. Some applications provide detailed, structured logs that SIEM systems parse easily. Others dump cryptic messages that require custom parsing rules. Standardising application logging dramatically improves SIEM effectiveness.
William Fieldhouse, Director of Aardwolf Security Ltd, notes: “SIEM implementation is just the beginning. The real work involves tuning detection rules, eliminating false positives, and actually investigating alerts. Many organisations spend heavily on SIEM licences but lack the staff to use them effectively.”
Log volume overwhelms storage capacity quickly. High-traffic environments generate terabytes of logs daily. Long-term retention costs substantial money. Organisations must balance retention requirements with budget constraints, often archiving less useful logs while keeping security-relevant data accessible.
Alert fatigue destroys SIEM effectiveness. When security teams receive hundreds of low-priority alerts daily, they begin to ignore them. Critical alerts get lost in the noise. Proper tuning reduces false positives without missing real attacks.
Detection rules require continuous refinement. Initial rules generate too many false positives. Overly aggressive tuning creates blind spots. Finding the right balance demands a deep understanding of both your environment and attacker techniques.
Correlation rules identify attack patterns spanning multiple events. A single failed login might be innocent. Fifty failed logins from different accounts in rapid succession signal an attack. Effective correlation requires understanding normal behaviour patterns.
Use case development drives SIEM value. Rather than simply collecting logs and hoping something useful emerges, organisations should define specific detection use cases. What attacks should we detect? What events indicate compromise? Clear use cases guide rule development. Professional internal network penetration testing validates whether your SIEM detects real attack techniques.
Investigation playbooks guide analysts through alert triage. When an alert fires, what should the analyst check first? What additional evidence confirms or refutes the alert? Documented procedures ensure consistent, thorough investigations.
