How can SF reach out to MAS ERP to capture data on demand

We'd like to find out our options to reach out to our ERP on demand. When we pull up an account, we need to know in real time if an account is on credit hold. We don't need a full integration, just this one piece. The data won't store in SF, we just need to have a flag showing that an account is on Credit Hold per our ERP (MAS 500).
We just don't know (1) is it possible and (2) what approach to take. We would like some guidance.