  Software Defined Wide Area Network (SD-WAN or SDWAN) is a modern conception
and an attractive trend in network technologies. SD-WAN is defined as a
specific application of software-defined networking (SDN) to WAN connections.
There is growing recognition that SDN and SD-WAN technologies not only expand
features, but also expose new vulnerabilities. Unfortunately, at the present
time, most vendors say that SD-WAN are perfectly safe, hardened, and fully
protected. The goal of this paper is to understand SD-WAN threats using
practical approach. We describe basic SD-WAN features and components,
investigate an attack surface, explore various vendor features and their
security, explain threats and vulnerabilities found in SD-WAN products. We also
extend existing SDN threat models by describing new potential threats and
attack vectors, provide examples, and consider high-level approaches for their
mitigations. The provided results may be used by SD-WAN developers as a part of
Secure Software Development Life Cycle (SSDLC), security researchers for
penetration testing and vulnerability assessment, system integrators for secure
design of SD-WAN solutions, and finally customers for secure deployment
operations and configurations of SD-WAN enabled network. The main idea of this
work is that SD-WAN threat model involves all traditional network and SDN
threats, as well as new product-specific threats, appended by vendors which
reinvent or introduce proprietary technologies immature from a security
perspective.
