WiFi access point (AP) security is one of the most important aspect when it comes to securing networks. The compromise of a WiFI AP (which mostly also double-up as router in SOHO environments) can lead to several secondary attacks. There are multiple vectors which are used to compromise the WiFi AP ranging from default passwords to sophisticated 0-days. But, after compromising the device, avoiding detection and maintaining access are the most important areas which eventually dictates the impact of the compromise. In this presentation, we will cover how to develop rootkits for WiFi APs to achieve stealth and persistence. We will be using OpenWRT for the demos. We will be covering the following in the presentation: 1. Introduction to OpenWRT 2. OpenWRT architecture and components 3. Understanding the OpenWRT build system 4. Compiling firmware 5. Compiling userspace application 5. Compiling kernel modules 6. Developing and deploying a hello-world rootkit 8. Adding capabilities to hello-world rootkit: a - Hiding itself b - Monitoring System calls c - Resisting kill d - Network stack backdoor 9. Conclusion and Q and A Attendees will get access to cloud based build system lab so they can try out the compilation and tinker if code.