Today, "SD-WAN" is a very hot and an attractive topic. Software-defined WAN (SD-WAN) is a technology based on software-defined network (SDN) approach applied to wide area networks (WAN. According to Gartner’s predictions study, more than 50% of routers will be replaced with SD-WAN solutions by 2020. At the same time, from a security point of view, SD-WAN is a dangerous mix of Web technologies, custom cryptography, virtualization, immature features and complicated logic.In this talk, we describe most common classes of design flaws and vulnerabilities in SD-WAN, disclose a set of reported and already patched vulnerabilities in popular SD-WAN products. We present the new results of our research, consider some technical details of the insecure design and found vulnerabilities. We also deeply explore a design flaw in a well-known SD-WAN product that could allow an attacker to compromise all SD-WAN networks in the World.