With this application you can extract attachments of the mails of your inbox to local folder via the EWS API. This program uses oauth and the ADAL.NET package 2.29.0.
Simply register the app with your office 365 account on https//portal.azure.com and put the app ID into the settings file.
If somebody wants to contribute in any way or upgrade to ADAL.NET 3.xx.x and implement this with oauth2 I'll happily add you as a developer.