Email flooded overnight with junk

Question

Email flooded overnight with junk

Mireille Chiasson 0

Hello

My main inbox - not the junk. Has been flooded with dozens of junk emails.. fake registrations.. its like someone took over my email account. So many suspicious activity. Too many to go through and individually identify as junk.. this is scaring me and i am not sure what to do.

Thanks

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2 answers

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Answer 1

EmilyS726 272.9K Independent Advisor

This sounds like a possible subscription/spam bombing attack.

This happens when someone uses your email address to automatically sign up for hundreds or thousands of newsletters or websites. The important part is that the flood can sometimes be used to hide a legitimate security alert, purchase confirmation, password change, or financial transaction among all the unwanted messages. Cybersecurity agencies specifically warn about this tactic.

I would not mass-delete everything yet. Search the messages for things such as order, purchase, payment, password, security alert, verification, Amazon, PayPal, bank, etc., and check your important accounts directly for any activity you do not recognize.

The email flood itself does not necessarily mean your Outlook account was hacked. Someone only needs to know your email address to carry out this type of attack, by going to legitimate websites and input your email address to create accounts, or sign up for newsletters.

A free article covering the same tactic is IT Brew’s March 20, 2026 report, which says security professionals are seeing an increase in subscription bombing, where bots overwhelm inboxes with legitimate newsletters and registrations to obscure fraudulent activity. https://www.itbrew.com/stories/2026/03/20/attacking-the-inbox-it-pros-seeing-rise-in-subscription-bombing

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This happened to me once a few years ago but it was my gmail address then. Unfortunately there's no way to get rid of these emails right away, other than going through as many as you can and unsubscribing. Most emails have the unsubscribe option at the end of the email body. It took me days to calm this down, so it can take some time.

Mireille Chiasson 0 Reputation points

2026-09-23T13:07:18.53+00:00

i did do what you advised not too which is to delete the emails - block senders.. but i have found the illicit transaction that i think they were trying to hide which was a plane ticket purchase via my Affirm account.
EmilyS726 272.9K Reputation points Independent Advisor

2026-09-23T13:14:43.94+00:00

Yes, back then with my case, they were trying to hide my credit card's alert email because they used it to buy a laptop at Apple store. Take care of the financial part of things first. Be aware, this can happen to your phone too, in my case, they also signed up my phone number for all kinds of business texting campaigns, with the same intention to bury important text from my credit card company. You might want to contact your cell company and ask them to put a esim block on it, in case they also try to steal your esim and transfer your phone number to their device, that way they can also access all 2FA/MFA codes for your accounts.

And btw, I did contact police and file a report - in case you need to deal with insurance or a credit card company for a fraud report, etc.

All of this can take some time to stop. Focus on preventing the financial loss first. Best luck to you!!
Mireille Chiasson 0 Reputation points

2026-09-23T13:21:09.54+00:00

Thank you soo much Emily.. i greatly appreciate you help.
EmilyS726 272.9K Reputation points Independent Advisor

2026-09-23T13:36:37.1733333+00:00

You are welcome.

Answer 2

This can be either a spam flood or a sign the account was compromised. Start with the checks that confirm which one it is:

Check Sent Items.
- If suspicious messages are in Sent Items, treat the account as compromised.
- If they are not in Sent Items, it can still be spoofing or a spam campaign, but security checks are still important.
Check recent sign-in activity.
- Review the recent activity page to see when and where the account was accessed, including successful sign-ins and security challenges.
- If anything looks unfamiliar, secure the account immediately.
Change the password to a strong, unique password and make sure multi-factor authentication is turned on.
- This is the most important protection step.
Check for suspicious inbox rules.
- Look for rules that automatically forward mail, delete mail, or move messages to folders such as Junk Email, Notes, or RSS Subscriptions.
- Remove any rule that was not intentionally created.
Report the unwanted messages as junk or phishing instead of trying to block them one by one.
- Blocking individual senders often does not help when spam uses constantly changing addresses.
- Reporting helps improve filtering.
Use Outlook junk settings to reduce the flood.
- In Outlook on the web: Settings > Mail > Junk email.
- Add trusted contacts to Safe senders.
- Add obvious bad senders or domains to Blocked senders and domains when patterns are clear.
If legitimate mail is being misclassified later, open the Junk Email folder and use It’s not junk for safe messages.
If the mailbox shows stronger compromise symptoms, act on them immediately.
- Warning signs include missing or deleted email, suspicious messages in Deleted Items or Sent Items, frequent password changes, unexplained lockouts, or recently added forwarding.

Useful signs from the current symptoms:

A sudden flood of fake registrations can happen during a spam campaign.
Missing mail, suspicious rules, forwarding, or sent mail that was not created are stronger indicators of account compromise.