Security log analysis forms the foundation of threat detection, incident response, and compliance. This guide covers log sources, analysis techniques, and how to build an effective monitoring program.
Why Log Analysis Matters
Logs provide visibility into every system interaction, enabling detection of anomalies, active attacks, and policy violations. Without proper log analysis, threats can persist undetected for months.
Effective log analysis combines automated pattern detection with human investigation. Modern attackers understand logging systems and attempt to avoid or corrupt them, making comprehensive collection and protection essential.
Critical Log Sources
A complete security monitoring program collects and correlates logs from multiple sources:
Authentication Logs
Track login attempts, failures, privilege escalations, and session activity. Critical for detecting credential attacks.
Firewall & Network Logs
Monitor connections, blocked traffic, and network flows. Essential for detecting lateral movement and data exfiltration.
Application Logs
Capture application-layer events including errors, API calls, and user actions. Reveals attacks that bypass network controls.
System Logs
Operating system events including process creation, file access, and configuration changes. Detects malware and persistence mechanisms.
Continuous Security Monitoring
Effective monitoring requires automation to process log volumes and alert on significant events:
- Real-Time Alerting - Configure alerts for high-priority events like failed authentications from known malicious IPs, privilege escalations, or connections to C2 servers.
- Anomaly Detection - Establish baselines and detect deviations in login times, access patterns, data volumes, and geographic locations.
- Threshold Monitoring - Set thresholds for events like failed logins, error rates, and bandwidth usage to detect attacks in progress.
Key Indicators of Compromise
Train your analysis to identify these common attack indicators:
- Multiple failed logins followed by a success (credential stuffing)
- Connections to known malicious IPs or C2 infrastructure
- Unusual process execution or privilege escalation
- Large data transfers outside business hours
Log Analysis Best Practices
Build a mature log analysis program with these practices:
- Centralized Collection - Aggregate all logs in a SIEM or log management platform for correlation and searchability.
- Proper Retention - Retain logs for at least 90 days for investigation, longer for compliance. Protect logs from tampering.
- Threat Intelligence Correlation - Enrich logs with IP reputation data to automatically flag connections to known malicious infrastructure.
- Regular Review - Schedule regular log reviews beyond automated alerts to identify trends and tune detection rules.
Related Articles
Continue learning with these related guides:
- SIEM Integration Guide - Learn how SIEM platforms centralize and correlate security data
- Incident Response Planning - Build an effective incident response program
- Threat Hunting Fundamentals - Proactively hunt for threats in your environment
Conclusion
Effective log analysis is the foundation of security operations. By collecting comprehensive logs, correlating with threat intelligence like Fraudcache, and building automated detection, you can identify threats quickly and respond before significant damage occurs.
Enhance Log Analysis
Correlate your logs with Fraudcache threat intelligence to automatically identify connections to malicious infrastructure.