Office 365 Email Is Vulnerable to Attack Without These Critical Supplementary Defenses in Place

With over 200 million users actively subscribed to Office 365 for email and collaboration services, Microsoft has clearly demonstrated its domination in the realm of computer software, technology and related services. However, with the recent proliferation of Office 365 use for business, one troubling trend has become increasingly apparent: inadequate built-in security defenses and unpatched vulnerabilities frequently leave users and critical data vulnerable to attack in Office 365.

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Exchange Online Protection (EOP) - the default, single-layered security defenses provided in Office 365, is unable to anticipate and block emerging attacks, and there are no preventative measures in place to combat zero-day exploits. Microsoft is an expert in technology - not in email security, and the reality is that users must look elsewhere for effective cloud email protection. Fortifying Office 365 email requires layered supplementary security defenses designed specifically to fill the dangerous gaps in Microsoft’s built-in cloud email protection.

The State of Office 365 Security (Or Insecurity?)

Office 365 security issues are nothing new; however, their impact has only been magnified by businesses’ growing dependence on the popular cloud platform to fulfill remote workers’ collaboration and communication needs. Cyber criminals are increasing both the volume and sophistication of attacks targeting cloud email users, as they experience heightened success with the widespread adoption of Office 365. 

With Office 365’s immense user base, threat actors are deeply invested in compromising its security, and are designing their attacks specifically to evade EOP’s security defenses. Due to the inherent uniformity of Office 365’s architecture, malicious actors are able to open any account and test their methods until they are able to bypass default filters. These methods can then be reused in attacks targeting thousands of different accounts.

Although Office 365 is the most widely used cloud service, Microsoft has consistently demonstrated an inability to protect users from credential phishing and account takeovers. A plethora of malicious phishing emails bypass EOP’s security defenses, which is highly problematic given that, according to the FBI, 30% of these phishing attempts are opened by target users. Osterman Research confirms the magnitude of the issue, reporting that 40% of users have experienced credential theft in Office 365. 

Security vulnerabilities are another persistent threat to Office 365 users. In an effort to rapidly identify security bugs in Office 365, Microsoft has launched a public bug bounty program for the platform. While this initiative builds some degree of security into Office 365, it has also confirmed the serious ongoing risks that Office 365 users face online. On a journey towards discovering 365 valid bugs in Office 365, Hyundai AutoEver Europe security engineer Ashar Javed has identified hundreds of vulnerabilities ranging from low severity to critical - with the majority rated by Microsoft as high severity flaws. Recently, a severe flaw in Microsoft EOP referred to as “Zerologon” has been actively exploited, allowing malicious actors to easily compromise computers on their same Local Area Network (LAN), install additional malware and steal sensitive data - without stealing credentials beforehand.

Fortify Office 365 Email with Critical Additional Layers of Proactive Security

In order to make Office 365 safe for business, organizations must implement layered supplementary security defenses that prevent both known and emerging attacks, as opposed to responding to them after-the-fact - once damage is already done. An effective supplementary cloud email security solution should leverage advanced intelligence provided by the vibrant, global open-source community, enabling it to constantly learn from  previously unknown threats that challenge it and update its protection in real-time to prevent future exposure to these exploits. 

Modern threats must be addressed with a defense-in-depth approach - no piece of antivirus software or spam filter alone is sufficient in detecting today’s advanced attacks such as spear phishing, fileless malware and zero-day exploits. Protecting against modern threats is a task that demands multiple layers of AI- and OSINT-powered defenses including malicious URL protection, email authentication protocols and impersonation analysis. These features must be designed to work harmoniously both with each other and with EOP’s existing protection to safeguard businesses’ users and critical data in Office 365.

Selecting a supplementary solution that provides ongoing, expert system monitoring, maintenance and support can further enhance Office 365 email security. Managed services can also simplify administration, provide the invaluable peace-of-mind that the security of your email is being overseen by a team of experts and free up valuable IT resources - delivering a rapid return on investment (ROI).

In addition to ensuring that you have fortified Office 365 email with layered supplementary cloud email defenses, other tips for safeguarding your data and remaining secure and productive in Office 365 include:

• Choose a strong password and enable multi-factor authentication (MFA) for all accounts.
• Ensure that Azure AD password sync is correctly configured.
• Enable mailbox auditing and unified audit logging in the Security and Compliance Center.
• Disable legacy email protocols (if not required).

Ready to reap the benefits of Office 365 without the risk? Learn about a threat-ready, fully-supported solution designed to make Office 365 email safe for business. Learn More>