(Pwn2Own) Western Digital MyCloud PR4100 restsdk Directory Traversal Arbitrary File Read and Write Vulnerability

This vulnerability allows remote attackers to create and read arbitrary files on affected installations of Western Digital MyCloud PR4100 NAS devices. Although authentication is required to exploit this vulnerability, the existing authentication mechanism can be bypassed. The specific flaw exists within the restsdk binary. The issue results from the lack of proper validation of a user-supplied path prior to using it in file operations. An attacker can leverage this in conjunction with other vulnerabilities to execute arbitrary code in the context of root.