Mail Delivery Failure messages for emails I didn't send

[Mal]

Recently I've been getting a ton of "Delivery to the following recipient failed permanently:" messages, and similar things. The problem is, I never sent the emails in question. They're always in Chinese, with some numbers included sometimes, and the messages are in my sent mailbox. I used Google Translate and they appear to be some fairly generic spam messages. I'm changing my password now, but does anyone know how this might have happened? I know I didn't get phished (I'm always careful about entering any information on websites, and never from a link in an email or anything), although it's possible the password could've been guessed (it wasn't the most difficult one ever).

Just want to help prevent it from happening again.

jW

 

[Intell]

The spammer could have altered the email headings to make it appear that the emails where being sent from your account. But I really don't know much about the inner workings of the email system so I could be wrong.

 

[Mal]

I would've assumed that if it weren't for the fact that they did show up in my sent box. That implies that I got hacked, most likely. I'm not 100% sure, though.

jW

 

[Decrepit]

Definitely a spoof. Report it to your ISP (and your mail host if it's not the same as your ISP), but there isn't a lot you can do about it.

 

[Decrepit]

I would've assumed that if it weren't for the fact that they did show up in my sent box. That implies that I got hacked, most likely. I'm not 100% sure, though.

jW

You most likely did not get hacked. It's more likely that your mail host is receiving the failed to deliver notices and it's being sent back down to you.

Basically PersonA sends PersonB email saying it's from PersonC. When PersonB doesn't exist because they sent it to 100,000,000 combinations of characters trying to hit everybody, PersonC gets some of the failed to delivers because the headers were spoofed.