An innovative phishing campaign has been discovered that uses branded Microsoft Office 365 login pages to trick victims into believing they are logging into their genuine Office 365 account.

The phishing emails warn the user that a message synchronization failure has blocked the delivery of emails to the user’s account. A link is supplied with the anchor text “Read Message” which directs the user to a fake Office 365 login page where they can review the messages and decide what to do with them.

If the user clicks on the link, their email address will be checked and validated, and the user will be directed to the phishing page. What makes this campaign unique is the check allows the attackers to scrape the branded tenant Office 365 login page used by the company via HTTP GET requests. The company’s custom background and logo are added dynamically to the phishing page. If a company does not have a custom login page, the standard Office 365 background is used.

The login pages are clones of the tenant pages, so they are unlikely to be recognized as fake by users. The phishing pages are also hosted on legitimate cloud storage infrastructure. The domains include either the blob.core.windows.net or azurewebsites.net domains, which have valid Microsoft SSL certificates. The result is a highly convincing campaign that is likely to fool many employees into divulging their login credentials.

Microsoft Office 365 Users are Under Attack!

Microsoft Office 365 is the most widely adopted cloud service by user count and has more than 155 million active users. 1 in 5 U.S. employees use at least one Office 365 service and half of businesses that use cloud services use Office 365. With such high numbers it is no surprise that Office 365 users are being targeted.

What is of major concern is the number of phishing emails that are bypassing standard Office 365 phishing defenses. A study by Avanan this year showed 25% of phishing emails bypass Office 365 defenses and arrive in employees’ inboxes.

When access is gained to one email account, it can be used for lateral phishing attacks on other employees in the organization. The goal of the attackers is to compromise as many accounts as possible and, ideally, an administrator account. Compromised accounts can also be used for BEC attacks, credentials can be used to access other Office 365 resources, and email accounts can be plundered for sensitive data.

How to Protect Your Business and Block Office 365 Phishing Attacks

There are three key measures to take to improve your defenses against Office 365 phishing attacks. The most important step is to improve anti-phishing protections with a third-party anti-spam and anti-phishing solution.

SpamTitan can be implemented in minutes and will provide superior protection against phishing attacks on Office 365 accounts. The solution has been independently tested and shown to block more than 99.9% of spam emails and 100% of known malware. A sandboxing feature allows suspicious attachments to be detonated in a safe and secure environment where all actions are analyzed for malicious activity and DMARC authentication of emails provides protection from email impersonation attacks that usually bypass Office 365 filters.

No anti-phishing solution will provide total protection against phishing attacks, so it is important to ensure that employees receive security awareness training. The workforce should be taught about the risks of email attacks and how to identify phishing emails. With training, you can turn your employees into strong last line of defense.

Even the most security-conscious employee could be fooled into disclosing their Office 365 credentials by a sophisticated phishing email. It is therefore important to implement 2-factor authentication.

2-factor authentication requires a second method of authenticating users, other than a password, when they attempt to login from an unfamiliar location or new device. In the event of credentials being compromised, account access can be blocked by -factor authentication. However, 2-factor authentication is not infallible, so businesses should not rely on this measure alone to protect their Office 365 accounts.

If you want to find out more about improving Office 365 defenses, give the TitanHQ team a call today and book a product demonstration. SpamTitan is also available on a free trial to let you see the difference the solution makes before you make a purchase decision.