New Office 365 Phishing Attack Discovered

A latest Office 365 phishing attack has been recognized that uses warnings concerning message delivery failures to attract unsuspecting users to a website where they are requested to provide their Office 365 account particulars.

The new cheat was found by safety scientist Xavier Mertens during an examination of electronic mail honeypot data. The electronic mails closely resemble formal messages transmitted by Microsoft to warn Office 365 users to message distribution failures.

The phishing electronic mails contain Office 365 branding and warn the user that action should be taken to make sure the delivery of messages. The text notifies the user that Microsoft has found a number of undelivered messages which have not been delivered because of server jamming.

The user is informed the failed messages should be resent by manually re-entering the receivers’ electronic mail addresses or by clicking the handy “Send Again” button in the message body. Users are supposed to click the button instead of manually re-enter a number of electronic mail addresses.

If the user clicks the Send Again button, the browser will be started and the user will be presented with a webpage that appears precisely like the official Office 365 web page, complete with a login prompt where they are requested to type their password. The login box already has the user’s electronic mail address so only a password is needed.

If the password is typed, it will be seized by the attacker together with the paired electronic mail address, and the user will be redirected to the official Office 365 website and might not be conscious that electronic mail identifications have been seized.

Official non-delivery alerts from Microsoft seem very similar, but don’t have a link that users can click to resend the electronic mails. Nevertheless, as the messages have the correct branding and use a similar format, it is likely that a lot of receivers will click the link and reveal their identifications.

Contrary to several phishing campaigns, the messages are well written and don’t include any spelling errors, just a missing capital letter in the warning.  The trap is believable, but there is one clear indication that this is a cheat. The domain to which the user is directed is obviously not one used by Microsoft. That said, a lot of people don’t always check the domain they are on if the website appears official.

This Office 365 phishing attack emphasizes just how important it is to cautiously check the domain before any confidential information is disclosed and to halt and think before taking any action advised in an unsolicited electronic mail, even if the electronic mail appears official.