Or Yair
Or Yair (@oryair1999) is a security research professional with seven years of experience, currently serving as the Security Research Team Lead at SafeBreach. His primary focus lies in vulnerabilities in the Windows operating system's components, though his past work also included research of Linux kernel components and some Android components. Or's research is driven by innovation and a commitment to challenging conventional thinking. He enjoys contradicting assumptions and considers creativity as a key skill for research. Or frequently presents his vulnerability and security research discoveries internationally at top conferences he speaks at such as Black Hat, DEF CON, RSAC, SecTor, and many more.
Session
Quick Share (formerly Nearby Share) allows Android users to easily share files for four years now. A year ago, Google has introduced a Windows version.
Google's promotion of Quick Share for preinstallation on Windows, alongside the limited recent research, ignited our curiosity about its safety, leading to an investigation that uncovered more than we had imagined.
We studied its Protobuf-based protocol using hooks, built tools to communicate with Quick Share devices, and a fuzzer that found non-exploitable crashes in the Windows app. We then diverted to search for logic vulnerabilities, and boy oh boy, we regretted we hadn’t done it sooner.
We found 10 vulnerabilities both in Windows & Android allowing us to remotely write files into devices without approval, force the Windows app to crash in additional ways, redirect its traffic to our WiFi AP, traverse paths to the user’s folder, and more. However, we were looking for the holy grail, an RCE. Thus, we returned to the drawing board, where we realized that the RCE is already in our possession in a form of a complex chain.
In this talk, we’ll introduce QuickShell - An RCE attack chain on Windows combining 5 out of 10 vulnerabilities in Quick Share. We’ll provide an overview about Quick Share’s protocol, present our fuzzer, the found vulnerabilities, a new HTTPS MITM technique, and finally the RCE chain.