Spam overload

[bungeejumper]

Strange thing happened to the wife's email account last night. She got eight apparent "responses" to emails that she'd sent more than two years ago to two separate county councils. (No, we didn't open them.) Plus two more emails about an email quota being 90% full, or something like that.

Swiftly followed within a matter of minutes by no less than 694 emails, all containing the same trojan, all of which were automatically quarantined by Kaspersky antivirus (and finally killed off by me this morning).

Then, an hour later, an email that she had sent to a friend was bounced back as non-deliverable because apparently her provider had been blacklisted by Hotmail.

This morning, all was peace and loveliness again. Can anyone explain what happened there? It certainly seems to me that somebody must have cracked the address books of two county councils simultaneously. But goodness, surely that sort of breach cannot be?

BJ

[UncleEbenezer]

Have you considered the possibility of a glitch at your ISP (or email provider if different) whereby a backlog or spam folder was inadvertently dumped on you?

And how do you know none of the responses from the county councils were real (possibly having been unseen for a long time due to some problem either at your end or with your ISP)?

[Infrasonic]

Then, an hour later, an email that she had sent to a friend was bounced back as non-deliverable because apparently her provider had been blacklisted by Hotmail.

That would seem to indicate it was an ISP/email provider issue as per UE's post (maybe they were doing maintenance/upgrades?).

Generally the bigger players are more adept at blacklisting temporarily when there are spam or configuration issues at the SMTP end, so it should resolve itself.
Blacklists tend to vary in what they monitor, some are specifically set up for configuration issues. So if you find out which lists you were on at the time of the problem that would clue you in more to what it was.
Reputational bounce backs or spam foldering can be mitigated somewhat by putting addresses into webmail contacts (ideally at both ends), if general whitelisting isn't enough.
If you do test emails between your own different accounts when you have deliverability issues then you can analyse the message source headers from both ends as well, to see any potential issues there.

https://mxtoolbox.com/NetworkTools.aspx