A day ago noticed a bunch of MAILER-DAEMON@yahoo.com emails in my Yahoo inbox. I checked my sent folder, and it appears that someone sent emails to all my contacts in my contact books with the following URL in the body (do not visit)
This is an email address I do not frequently use (I check once every couple of weeks), so I went to my recent activity which shows devices and IPs that have connected in the past 30 days, but there is nothing suspicious there - they're all IPs I recognize.
I do not use a mail client, such as Outlook or Thunderbird, only Yahoo mail in the browser, and on the iPhone.
My question is... how is it that without any recent activity did the hacker send an email without triggering any recent activity?