Microsoft has just announced that SMB v1 will be disabled by default on some virtual machines from the Marketplace.
This follows the major situation some weeks ago with malwares/ransomwares taking advantage of flows in the SMB protocol (which were patched by not always deployed).
You can read this post to get the list of virtual machine going to be ‘impacted’ https://blogs.msdn.microsoft.com/azuresecurity/2017/08/18/disabling-server-message-block-version-1-smb-v1-in-azure