Email spoofing?

[OhYouBadBadKitten]

We've had a warning letter from our isp that a lot of junk mail seems to be coming from one of our accounts. I think it is dds email account because I've had an odd email as has dh with her address being as the sender. The other emails addresses that they are sent to are a very random selection of people we know and don't know.

We all run decent av on our laptops. Scans have been run and we ran a recommended online scanner on our equipment too. dd has an android tablet and phone, but she says she has run an av on those.

There is nothing in her sent box at all. She has changed her password twice to very secure passwords - she uses random generators. Yet this morning I had another email apparently from her.

It is a bit rotten luck - she uses throwaway email accounts when she signs up to stuff.

My guess is that her email addy has been spoofed. What do we do now?

[OhYouBadBadKitten]

oh yes - todays dodgy email was sent a couple of hours after she left for school. Her lap top and other devices are turned off.

[codewaist]

Do you have other computers on your home network that are on all the time that could be running an open mail relay?

en.m.wikipedia.org/wiki/Open_mail_relay

[OhYouBadBadKitten]

My computer was on at the time, but how would I know if it were running an open mail relay?

I contacted the security team at our ISP on Friday. Heard nothing.