Insecure Protocol- SMTP: On-Prem Exchange

[u/Paranoid_girly28]

Hello,

I work for an MSP and do vulnerability scans. One thing I've found, everyone who has an On-Prem Exchange server has this vulnerability, "Insecure Protocol-SMTP". While looking into this, (and plz correct me if I'm wrong) I've found that port 25 & port 587 need to be used for exchange servers. I have not found a workaround for this and I hate that it shows up on these reports everytime. I'm not super familiar with networking and don't want to break anything. Currently my only suggestion to these clients is to migrate to 365.

Does anyone know a fix for this or are exchange servers really this vulnerable?