This happened to me before. I used a certain email address for school so my students were able to use it whenever they needed to send a assignment over the email. Recently I noticed that one of my students has sent me spam. I see her name in the sender field and the message title is something like “No regrets after doing this venture! Are you sick of lending money…” or another messages says “Re: Re: Hey, how are you?” The messages contain a link that is supposed to help you if you are in debt.
My student did not send me these messages but after doing some investigation, here’s what I think happened.
Sometimes spammers can get the email addresses of all your contact lists from your email account. There may be a virus that you, unknowingly, let collect information about your contacts and all your contacts may be receiving irritating advertisements that appear to have been sent from your address. Or, you get email spam from your contacts and your contacts did not send them, as in the above example with my former student. But somehow these contact lists have been hacked, especially with Yahoo and Hotmail accounts.
When you see you get spam from your contacts or even from your own email address, then you should report these messages to your email provider and delete your contacts list.
I do not keep a contact list in my yahoo account anymore and I can say that I haven’t received spam in my regular inbox ever since.