I recently noticed a `.NET` software using `PBKDF` to derive an encryption key from a password string. This password string was dynamically generated using `System.Random`. Now, I know that `System.Random` is not really cryptographically random and should not be used for security purposes. Moreover, there are [several flaws](https://stackoverflow.com/questions/1257299/why-use-the-c-sharp-class-system-random-at-all-instead-of-system-security-crypto) in `.NET`'s implementation of `System.Random`. 

But my question is this:

* What is the *practical* impact of using System.Random to create a password string and deriving a key from it. Is it really possible for us to reproduce the key at a later time? Are there *feasible* attacks that will allow me to deduce the random string generated in this context with high probability? Or is it the kind of vulnerability that can only be exploited in specific "lab" conditions or scenarios?