Many services and daemons are subject to MitM (man in the middle) attacks and eavesdropping. With eavesdropping, unauthorized parties can learn logon credentials or confidential information. Many services do not require end-point authentication or use encryption. Some new operating systems are knowingly released with outdated libraries and vulnerable binaries. You can download every patch the vendor has to offer and you’re still exploitable. Follow all the normal security defense advice: Inventory your network and get a list of all listening services.”]
Source: https://www.csoonline.com/article/2633153/protect-against-external-threats.html