Explore the intricacies of macOS firewall development and vulnerabilities in this 25-minute Black Hat conference talk. Dive into core concepts like kernel-level socket filtering, user-mode component communication, secure privileged code installation, and self-defense mechanisms implementation. Learn about firewall vulnerabilities, including generic bypasses, DNS abuse, browser exploitation, and kernel-based bypasses. Gain insights into creating effective macOS firewalls while understanding potential weaknesses and attack vectors. Presented by Patrick Wardle, this comprehensive talk covers topics from socket filter registration to finale, providing valuable knowledge for both security professionals and macOS enthusiasts.