Saia Burgess Controls (SBC) PCD through 2022-05-06 allows Authentication bypass

Saia Burgess Controls (SBC) PCD through 2022-05-06 allows Authentication bypass. According to FSCT-2022-0062, there is a Saia Burgess Controls (SBC) PCD S-Bus authentication bypass issue. The affected components are characterized as: S-Bus (5050/UDP) authentication. The potential impact is: Authentication bypass. The Saia Burgess Controls (SBC) PCD controllers utilize the S-Bus protocol (5050/UDP) for a variety of engineering purposes. It is possible to configure a password in order to restrict access to sensitive engineering functionality. Authentication functions on the basis of a MAC/IP whitelist with inactivity timeout to which an authenticated client's MAC/IP is stored. UDP traffic can be spoofed to bypass the whitelist-based access control. Since UDP is stateless, an attacker capable of passively observing traffic can spoof arbitrary messages using the MAC/IP of an authenticated client. This allows the attacker access to sensitive engineering functionality such as uploading/downloading control logic and manipulating controller configuration.