Someone is using my Outlook to send emails with attachments to my contacts

It sounds like your Outlook account has indeed been compromised. Here are some steps you can take to regain control and secure your account:

1. Check for Suspicious Activity: Sign in to your Outlook account and review the recent activity. Look for any unfamiliar sign-ins or changes.
2. Change Your Password: Since your web administrator has already changed your password, ensure that you are using a strong, unique password that you have not used before.
3. Enable Multi-Factor Authentication (MFA): If you haven't already, enable MFA on your account. This adds an extra layer of security by requiring a second form of verification when signing in.
4. Review Account Permissions: Check for any apps or services that have access to your account. Revoke access to any that you do not recognize or use.
5. Check for Rules and Forwarding: Sign in to Outlook Web and check the settings for any suspicious rules or forwarding addresses that may have been set up by the hacker.
6. Sign Out of All Sessions: Use the option to sign out of all active sessions to ensure that any unauthorized access is terminated.
7. Contact Microsoft Support: If you are unable to regain access or if the issue persists, consider contacting Microsoft support for further assistance.
8. Monitor Your Account: Keep an eye on your account for any further suspicious activity, and be cautious of any emails that may appear to be sent from your account.

Taking these steps should help you regain control of your account and prevent further unauthorized access.

References:

• Responding to a compromised cloud email account
• Hacker set up continuous draft ransomware email
• Unblock my Outlook.com account
• Outlook is using a temporary email and I cannot receive emails
• Outgoing emails with attachments undelivered as spam