Falco — Watching Linux and Containers at Runtime
Why It Matters
Falco is often described as a runtime security tool, but in practice it feels like a watchdog sitting inside your Linux host or Kubernetes node. Logs and IDS tools see what already happened, while Falco pays attention to what the kernel is doing right now. That’s useful if someone spawns a shell inside a container, changes critical files, or starts probing the system in ways that don’t look normal. For teams running clusters, it covers a blind spot traditional monitoring tends to miss.
How It Works
Falco hooks into system calls using eBPF (older installs still rely on a kernel module). Every syscall is checked against a set of rules — the defaults cover common attack patterns, and admins can write their own. If something matches, Falco raises an alert. Those alerts can end up in syslog, a JSON feed, or get piped straight to tools like Prometheus, Grafana, or a SIEM. The point is speed: alerts fire the moment the action happens, not after logs are processed.
Technical Notes
| Aspect | Details |
| Platform | Linux hosts, VMs, Kubernetes/Openshift nodes |
| What it watches | Syscalls, processes, file access, network activity |
| Detection style | YAML rule sets — default policies plus custom ones |
| Output channels | Syslog, JSON, gRPC, integrations with dashboards and SIEMs |
| Container focus | Native Docker and Kubernetes support |
| License | Apache 2.0, open source |
Deployment Notes
1. Install via package manager, Helm chart, or directly from GitHub.
2. Load the eBPF driver (preferred) or kernel module.
3. Start with the default rule pack, then add custom rules specific to your workloads.
4. Decide how alerts are handled — log files, syslog, or external pipelines.
5. Test by simulating a suspicious action (e.g., run bash inside a pod).
Where It Fits
– Kubernetes workloads where containers need runtime oversight.
– Bare Linux servers where detecting privilege escalation or tampering matters.
– SOC pipelines, feeding Falco alerts into SIEM for correlation.
– DevSecOps environments where runtime checks are baked into daily operations.
Caveats
– No prevention on its own — Falco only alerts; blocking needs another layer.
– Rules take tuning, otherwise false positives show up.
– Linux only; no Windows driver.
– In high-volume clusters, alert noise can become a challenge until policies are tightened.