Toru Makabe

Microsoft Threat Intelligence observed an active phishing campaign exploiting the Microsoft 365 service disruption on November 12. The messages impersonate Microsoft 365 service health notifications and reference the legitimate Exchange Online incident EX1550543. Some of the phishing emails Microsoft detected on November 13 falsely claim that messages were held during the outage and will be deleted within 24 hours unless recipients click to restore them. Observed subjects follow the pattern "Outage - [six-character code]," with sender display names using organization-specific prefixes followed by "Outage Notification" or "Service Health." The campaign uses three sender domains, moments-notice[.]com, planetmaison[.]com, and newbooker[.]com, with recipient-specific SendGrid click-tracking links redirecting to reallifeaccounting[.]com, including the observed path /themelist0.html. Similar messages targeted organizations across multiple US sectors. The activity is consistent with credential phishing, although credential collection and malware delivery have not been confirmed. Security teams can use Microsoft Defender for Office 365 Threat Explorer and Microsoft Defender XDR advanced hunting (EmailEvents, EmailUrlInfo, and UrlClickEvents) to identify suspicious messages, examine embedded URLs, and investigate user clicks. Microsoft Defender for Office 365 Safe Links provides time-of-click protection against malicious URLs when properly configured. Organizations should verify their Safe Links policies, investigate potential user interactions, and confirm service disruptions directly through the Microsoft 365 admin center.