Log Analysis Visualizer
Filter, inspect, and correlate real-format system, application, and security logs
// Log Format Reference
Different systems write logs in different formats. Knowing the structure lets you parse them reliably.
// Interactive Log Viewer
Entry Detail// Event Correlation Timeline
Events plotted across time — spot clusters of errors and correlate cross-source events.
// Pattern Detection Exercises
Apply your filtering skills to solve real analyst challenges.
Exercise 1 — Failed Login Attempts
A user account has been locked out and the security team suspects a brute-force attack.
Identify all failed login events and determine which user account was targeted most.
Hint: Filter by Type: Security, Severity: ERROR or CRITICAL, search "failed login".
Hint: Filter by Type: Security, Severity: ERROR or CRITICAL, search "failed login".
Exercise 2 — Disk Space Alerts
Capacity planning requires identifying which servers reported disk space warnings in the
last 24 hours. Find all disk-related alerts before a full disk causes a service outage.
Hint: Filter by Type: System, Severity: WARNING or ERROR, search "disk".
Hint: Filter by Type: System, Severity: WARNING or ERROR, search "disk".
Exercise 3 — Application Crash Correlation
The web application crashed twice overnight. Find the application errors, then check if
any system-level events (memory, CPU) occurred immediately before each crash.
Hint: Look for application CRITICAL events, then correlate timestamps with system WARNINGs.
Hint: Look for application CRITICAL events, then correlate timestamps with system WARNINGs.
// Log Analysis: Key Concepts
Centralized Logging
Aggregate logs from all hosts into one system (SIEM, ELK Stack, Splunk). Correlation
across sources is impossible when logs live on individual servers.
Log Parsing
Scripts extract fields (timestamp, severity, host, message) from raw text using
regex or structured formats like JSON/CEF. Parsed logs are queryable.
Retention Policy
Security logs: 90-365 days minimum (PCI/HIPAA requirements). System logs: 30-90 days.
Rotate and compress old logs automatically with logrotate or Task Scheduler.
Log Integrity
Forward logs to a write-once remote store immediately. An attacker who compromises
a host can delete local logs — remote forwarding (syslog-ng, Winlogbeat) prevents this.