Stay Ahead With Linux Security HOWTOs

One of the easiest mistakes to make in detection engineering is assuming a rule keeps working simply because nobody has touched it. Most of the time, nobody removes the rule. Nobody disables it. It just gets forgotten. . A few months later, someone upgrades a distribution, changes how SSH keys are managed, replaces a logging agent, or migrates an application to containers. The detection is still enabled, but it's watching an environment that no longer exists. The alert everyone expected never...

Docker makes containers feel like separate, lightweight virtual machines. They have their own hostnames, processes, and networking—but are they actually isolated? Many administrators assume they are without ever verifying the boundaries. If you’ve ever wondered what truly separates your application from the host, this guide is for you. We’ll use simple Docker commands to verify container isolation firsthand and uncover exactly what remains shared with the host. . What Is Container Isolation?...

You’re staring at a service or a cron job that’s giving you a bad feeling. Stop. The most dangerous thing you can do right now is act on that gut feeling alone. Linux systems are inherently noisy—package managers, configuration management, and the occasional "quick fix" from a colleague can all leave weird artifacts behind. . Step 1: Check Whether the File or Service Looks Normal When I'm looking at a scheduled task, I look for logic, not just anomalies. A cron job running...

Building effective behavioral detections starts with understanding how processes behave at runtime, rather than simply collecting more logs. eBPF gives Linux security teams the visibility needed to correlate those behaviors into meaningful detections, moving away from static signatures and toward real-time analysis. . The first surprise for most people coming from auditd or legacy log collectors is how much context suddenly becomes available. Instead of just seeing that a shell executed, you...

When a security alert fires, the panic often sets in before the analysis. Many administrators instinctively reach for /var/log/auth.log or journalctl , but those logs tell only a partial story. They document successful logins and authentication attempts, but they rarely capture the granular "how" of a post-compromise environment. To truly reconstruct an attack, you need to master audit logs . Unlike standard authentication logs, Linux audit logs (managed by auditd ) record system-level...