Automated dynamic firmware analysis at scale: A case study on embedded web interfaces

Embedded devices are becoming more widespread, interconnected, and web-enabled than ever. However, recent studies showed that embedded devices are far from being secure. Moreover, many embedded systems rely on web interfaces for user interaction or administration. Web security is still dicult and therefore the web interfaces of embedded systems represent a considerable attack surface. In this paper, we present the first fully automated framework that applies dynamic rmware analysis techniques to achieve, in a scalable manner, automated vulnerability discovery within embedded rmware images. We apply our framework to study the security of embedded web interfaces running in Commercial O-The-Shelf (COTS) embedded devices, such as routers, DSL/cable modems, VoIP phones, IP/CCTV cameras. We introduce a methodology and implement a scalable framework for discovery of vulnerabilities in embedded web interfaces regardless of the devices' vendor, type, or architecture. To reach this goal, we perform full system emulation to achieve the execution of rmware images in a software-only environment, i.e., without involving any physical embedded devices. Then, we automatically analyze the web interfaces within the rmware using both static and dynamic analysis tools. We also present some interesting case-studies and discuss the main challenges associated with the dynamic analysis of firmware images and their web interfaces and network services. The observations we make in this paper shed light on an important aspect of embedded devices which was not previously studied at a large scale.