(Pwn2Own) Phoenix Contact CHARX SEC-3100 CharxUpdateAgent Unrestricted File Upload Remote Code Execution Vulnerability

This vulnerability allows network-adjacent attackers to create arbitrary files on affected installations of Phoenix Contact CHARX SEC-3100 devices. Authentication is not required to exploit this vulnerability. The specific flaw exists within the CharxUpdateAgent service, which listens on TCP port 9999 by default. The issue results from the lack of proper validation of user-supplied data, which can allow the upload of arbitrary files. An attacker can leverage this in conjunction with other vulnerabilities to execute arbitrary code in the context of the service account.