A spearphishing attack is spoofing Microsoft.com to target 200 million Office 365 users in a number of key vertical markets. Financial services, healthcare, manufacturing and utility providers are being targeted. Ironscales researchers discovered the campaign targeting several thousand mailboxes at nearly 100 of the email security firm s customers. The attack is comprised of a realistic-looking email that attempts to persuade users to take advantage of a relatively new Office 365 capability that allows for them to reclaim emails that have been accidentally marked as spam or phishing messages.
Source: https://threatpost.com/spearphishing-attack-spoofs-microsoft-office-365/162001/