The Problem
A Linux server generates thousands of log lines per hour. Without structure, critical alerts drown in noise. Attackers rely on this.
Core Logs to Monitor
- /var/log/auth.log – SSH, sudo, login attempts.
- /var/log/syslog / messages – system and kernel alerts.
- journald – structured logging with filters.
- Application logs – Apache, Nginx, PostgreSQL, etc.
Practical Analysis Tools
- journalctl: filtering by user, service, or time window.
- ausearch: auditd-based forensic digging.
- logwatch/logcheck: daily digest reports.
- grep + awk pipelines: still powerful for ad hoc triage.
Applied Example
journalctl _COMM=sshd --since "1 hour ago"→ flags suspicious repeated SSH attempts in real time. Pair with Wazuh for automatic escalation.
Why Clients Care
- Faster incident response.
- Lower SOC fatigue from false positives.
- Direct tie-in to ISO 27001 logging requirements.
Security gaps in Linux and cloud systems risk downtime, data compromise, lost business — and compliance failures.
With 20+ years’ experience and active UK Security Check (SC) clearance, I harden Linux and cloud platforms for government, corporate, and academic sectors — ensuring secure, compliant, and resilient infrastructure.