Microsoft is advising administrators to disable the SMBv1 network communication protocol on Exchange servers to protect their servers from malware threats such as TrickBot and Emotet. In a new post to the Microsoft Tech Community, the Exchange Team is urging admins to disable it. Microsoft has been recommending that administrators remove support for SMBV1 on their network as it does not contain additional security enhancements added to later versions of the protocol. These enhancements include encryption, pre-authentication integrity checks to prevent man-in-the-middle attacks and more.
Source: https://www.bleepingcomputer.com/news/microsoft/microsoft-urges-exchange-admins-to-disable-smbv1-to-block-malware/