Why is my blog not on my dashboard - and why is somebody else publishing, and using my name?There are so many reports from people who are not using Google "One Account" login properly, that the significance of this problem report was initially overlooked.
More than a few such reports started with the blog owner email address being openly disclosed - generally on the blog, or in comments. Too many blog owners want to be contacted - and they innocently provide their email addresses as a contact point.
We've known, for years, about disclosed email addresses, and brute force password guessing. That is not the only way your email address can be used, to gain access to your Blogger account, however.