Threat Detection in Kubernetes with Falco

josepraveen Posted on May 30 Threat Detection in Kubernetes with Falco # falco # devsecops # tutorial # todayilearned Finding out there is "suspicious activity" in your infrastructure is enough to make any DevOps engineer's heart rate spike. If you’re running containerized workloads, you need a way to see exactly what’s happening inside those isolated environments in real-time. Falco , the open-source standard for cloud-native runtime security. In this guide, we'll walk through a hands-on scenario: investigating a suspicious Nginx container by detecting unauthorized spawning processes. A team member reports odd behavior in a specific container. Our goal is to use Falco to monitor the execve system call—which is triggered whenever a new process is started—and log those events to a report for analysis. Step 1: Create a Custom Falco Rule Falco uses a flexible YAML-based syntax for defining security rules. We need to create a rule specifically targeting our Nginx container. Create a new rules file: vi nginx-rules.yml Paste the following configuration: - rule : spawned_process_in_nginx_container desc : A process was spawned in the Nginx container. condition : container.name = "nginx" and evt.type = execve output : " %evt.time,%proc.name,%user.uid,%container.id,%container.name,%container.image" priority : WARNING Enter fullscreen mode Exit fullscreen mode Save and exit ( Esc , :wq , Enter ). Breakdown of the Rule: Condition: We are filtering for events where the container name is exactly "nginx" and the event type is execve (process execution). Output: This defines the format of our log, capturing the timestamp, process name, user ID, and container metadata. Why is this rule important? In a secure, production containerized environment, containers should follow the principle of immutability. An Nginx container should only run Nginx. If a hacker successfully exploits a vulnerability in your Nginx web server, the first thing they will often try to do is open a reverse shell