A Modbus connection feature on openPDC accepts a caller-specified destination address and port with no restriction on which internal hosts may be targeted. An authenticated user can attempt connections to arbitrary internal network destinations, revealing which destinations are reachable. With repeated attempts, an attacker may be able to map the internal network.
Weakness
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.