How to Combat Business Email Compromise in Microsoft 365 Environments

Cloud email servers are susceptible to countless email threats if they do not incorporate the right email protection software to ward off cybercriminals, who prioritize these systems since the attacks are relatively successful. Business Email Compromise and credential theft remain two of the biggest threats facing Microsoft 365, Google Workspace, and other cloud email platforms. The problem is growing fast. BEC attacks rose 171% in 2025, and security researchers recorded 10.7 million attacks during the first quarter of 2026 alone. This article will discuss BEC risks, how they harm a server, and what options you have to improve your security posture.

What Is Business Email Compromise?

Business email compromise is email fraud in which threat actors pretend to be a trusted coworker or business partner of their target. The purpose of these attacks is to persuade employees to send money or sensitive documents to the attackers. Threat actors understand that email security software can be bypassed by creating phishing email attacks that imitate server messages. Phishing attacks deceive employees into sending over data that leads to compromised email addresses, system crashes, and financial losses. 

During an attack, threat actors will often impersonate CEOs and higher-up individuals in a company through email spoofing attacks and compromised email accounts. Typically, it resembles a spear phishing email attack. BEC emails seek to gain information from victims and install malware or ransomware that can harm a business's reputation and finances. Then, threat actors can utilize this compromised data to launch additional attacks that severely damage a company's productivity.

Who Does Business Email Compromise Target?

Business Email Compromise can hit any email platform, but remote and hybrid teams carry more exposure. SMBs are often hit hardest. This is because they rely on cloud email while running lean IT teams.

Users need to be mindful of their security settings. Microsoft 365, Google Workspace, and similar platforms include security controls that can block BEC attempts, but many are not enabled by default. That gap matters. Small businesses should review and turn on cloud email protection before attackers exploit weak settings.

How Can Companies Prevent Business Email Compromise?

Digital workers should follow best practices for email security to add layers of protection. The following cybersecurity tools and recommendations can make their business safer: 

• Set up 2FA or MFA protocols for all email platforms to verify users before they access the server.
• Speak to known contacts to confirm payment or transaction changes to keep cybercriminals from learning your financial information.
• Train employees to recognize suspicious messages and use preventative strategies against Business Email Compromise and spear phishing attacks.
• Remove automatic email forwarding permissions to external addresses. This is an easy way for email spoofing attacks to unfold.
• Add email banners for messages from outside your organization to warn users. Quarantine emails that appear untrustworthy.
• Disable POP and IMAP if they aren't required. They create authentication gaps that attackers still look for.
• Keep enough login and message history to investigate an incident properly. Ninety days is usually a reasonable minimum.
• Alert on unusual sign-ins. Foreign logins, impossible travel events, and new devices are often the first sign that something is wrong.
• Scan links and attachments before they reach users.
• SPF, DKIM, and DMARC should be enforced, not just configured.

These email security best practices are essential for organizations to improve their security posture and keep their business, clients, and employees safe.

How Guardian Digital Helps Prevent Business Email Compromise

Business Email Compromise succeeds when attackers find a weak process, a misconfigured mailbox, or a user who trusts an email that looks legitimate. Guardian Digital focuses on these layers of the attack.

Messages are inspected in real time for signs of impersonation, phishing, account takeover activity, and social engineering tactics that often slip past traditional filters. The objective is straightforward. Stop malicious emails before they land in the inbox and turn into an incident ticket. 

Visibility matters too. Security teams need to know when attackers are probing accounts, spoofing domains, or abusing trusted business relationships. Blocking a message is useful. Understanding what the attacker was trying to do with it is often what helps prevent the next attempt.

For organizations with limited security staff, operational support becomes important. Most SMBs do not have analysts reviewing email telemetry around the clock or investigating suspicious login activity after hours. They are managing patches, identity controls, endpoint alerts, and everything else at the same time. Email security still needs attention.

The platform is cloud-based, which keeps deployment and management relatively simple as environments grow. Policies can scale without creating another system that requires constant tuning. Less time spent maintaining email defenses. More time is spent dealing with the threats that actually require investigation.

Business Email Compromise FAQs

These questions highlight crucial aspects of Business Email Compromise that are likely to come up in training. Review our answers to learn more:

What does a Business Email Compromise attack look like?

The email usually looks like normal business traffic. A vendor wants to update banking details, or an executive is asking for something "before the end of the day." The email often blends into hundreds of legitimate messages sent that same day.

What is the most common form of Business Email Compromise?

Payment and invoice fraud are among the most common forms of business email compromise. An attacker impersonates a supplier, vendor, or contractor and attempts to redirect an upcoming payment. In many cases, the activity begins with the same phishing threats used to gain access to business communications in the first place.

What industries are most targeted by BEC attacks?

In practice, BEC hits almost every industry because email is how business gets done. Manufacturing companies process large supplier payments. Healthcare organizations deal with complex vendor relationships. Law firms handle sensitive transactions. Real estate firms move large amounts of money quickly. Financial services are an obvious target. All of these complex communication networks create an ideal opening for attackers to impersonate employees.

How do hackers spoof email addresses in BEC attacks?

Sometimes they register a domain that looks almost identical to the real one. One letter changed. One extra character. Easy to miss when you're moving fast.

Attackers will also manipulate the display name so the sender appears to be someone you know. The more serious cases involve compromised accounts where the attacker is sending messages from a legitimate mailbox, which makes detection much harder because the email comes from a trusted source.

Can BEC emails come from a real company email address?

Absolutely. One of the toughest BEC cases to investigate is when the attacker is already inside a real mailbox. At that point, they're reading conversations, learning who approves payments, and watching how people communicate. When the fraudulent email arrives, it comes from an address everyone already trusts. No spoofing required. 

What does a fake CEO email look like in a BEC scam?

The email might say the CEO is in a meeting, traveling, or unavailable by phone. There's an urgent request. Maybe a wire transfer. Maybe gift cards. Maybe a sensitive document that needs to be sent immediately. 

Executive impersonation remains one of the most successful BEC techniques because employees are conditioned to respond quickly to senior leadership requests. This approach is known as whaling and is a type of phishing attack that specifically targets high-value individuals or the employees who support them. 

Keep Learning About Business Email Compromise

Business Email Compromise threats and other phishing email attacks are constantly rising, and companies should be thoroughly prepared to face them. One of the best approaches to BEC defense is learning how to prevent phishing attacks, because the risks are related. 

• Businesses can also consider supplementing their IT team with a cloud security service, such as Guardian Digital EnGarde Cloud Email Security.
• Our Microsoft 365 email protection guide is free to download for anyone who wants to learn more about protecting against cloud email vulnerabilities.