Rogue calendar event I have just had a mysterious thing happen: a calendar event has appeared out of nowhere.



At more or less the same time I received a similar email:



Now I am used to email spam, but how on earth has this calendar event infiltrated my machine?

I haven't opened any email attachment. Mail can't have opened an email attachment on my behalf, as that above email is the only email I've received today; it contains a single image attachment (not particularly exciting). I think this must be a red herring, as I had to specifically instruct Mail to display the image, and I only did this after receiving the calendar event.

And this calendar event appeared completely of its own volition. I was just staring at some document I have open in Preview.

Is my machine compromised?  Does it have some door open that should be closed?

I have never before had any anomalous occurrence in seven years of using Apple machines. What is going on here?

π

PS Also I have never used the calendar application.  I did purchase this machine second-hand about three months ago, so maybe something is left over from the previous user, but the machine came to me with a seemingly fresh OS X installation, so it seems unlikely.
Your Calendar must be set to automatically accept invitations from email.
CHECK FOR THIS SETTING:

Automatically retrieve CalDAV invitations from Mail
Select this checkbox to have Calendar get event invitations from Mail.

Go to Preferences in your Calendar and turn it off. (for now)

Next, set junk filtering in your Gmail.
Also block this specific user.
Just to make sure, change your Gmail password.
Clean all Internet saved browsing (the history) including cookies.
Then run a virus scanner to finalize.
Once you are sure you got your Gmail account under control with decent junk filtering, you can turn the auto Calendar invites on, if you wish to use it.
If there is a leftover from previous owner, check the Delegation set up in Calendar, by clicking on the EDIT. There should be no names in there.