This week, researchers from Wiz Research released a series of vulnerabilities in the Kubernetes Ingress NGINX Controller  that, when chained together, allow an unauthorized attacker to completely take over the cluster. This attack chain is known as IngressNightmare, and it affected over 6500+ Kubernetes installs on the public Internet.

The background here is that web applications running on Kubernetes need some way for outside traffic to actually get routed into the cluster. One of the popular solutions for this is the Ingress NGINX Controller. When running properly, it takes incoming web requests and routes them to the correct place in the Kubernetes pod.

When a new configuration is requested by the Kubernetes API server, the Ingress Controller takes the Kubernetes Ingress objects, which is a standard way to define Kubernetes endpoints, and converts it to an NGINX config. Part of this process is the admission controller, which runs nginx -t on that NGINX config, to test it before actually deploying.

As you might have gathered, there are problems. The first is that the admission controller is just a web endpoint without authentication. It’s usually available from anywhere inside the Kubernetes cluster, and in the worst case scenario, is accessible directly from the open Internet. That’s already not great, but the Ingress Controller also had multiple vulnerabilities allowing raw NGINX config statements to be passed through into the config to be tested. Continue reading “This Week In Security: IngressNightmare, NextJS, And Leaking DNA” →