A payment request hits an inbox, references a real project, and matches the tone your team expects from a vendor or executive. A controller approves it, funds leave your bank account forever, and no one is the wiser until much later.
That pattern describes business email compromise (BEC), a type of fraud that uses impersonation and stolen credentials instead of malware. It shows up in organizations of every size because it targets routine work: invoice approvals, bank detail updates, and “quick” requests that arrive when people are busy.
BEC prevention is not only an email problem. It sits at the intersection of identity security, mailbox configuration, and finance workflows. When those pieces are inconsistent, attackers find the gap. The best results come from tightening access, improving detection, and building payment steps that slow fraud without slowing the business.
This post examines how BEC attacks succeed and the practical controls that reduce your risk for businesses like yours.
What BEC looks like in real life
BEC tends to follow a few repeatable plays. Understanding the patterns helps teams recognize high-risk moments and put targeted checks in place.
The invoice swap
In an invoice swap, an attacker impersonates a vendor and sends “updated” bank details for an existing relationship. The message often includes a real invoice number, a current project name, and a request that feels routine. If Accounts Payable processes the update from email alone, the next payment goes to the wrong account.
Construction firms and professional services teams see this when subcontractors, consultants, and suppliers change frequently. The volume of legitimate payment changes makes a single bad one harder to spot.
The executive request
Some attackers pretend to be a senior leader and pressure a staff member to move funds or purchase gift cards. The request leans on authority and urgency, and it often arrives outside normal approval paths. Even when employees feel unsure, they may comply because they do not want to slow an executive down. These requests often come in the form of casual text messages or short emails.
Why standard email defenses miss these attacks
Many organizations expect spam filters to catch fraud. With BEC, the problem is not always a “bad” email. The problem is that the email matches normal business behavior.
BEC messages are short, specific, and built around tasks your team already performs. A request to “update banking” or “pay this invoice today” does not look like a typical phishing email. Attackers also register domains that resemble your vendor’s domain, which can fool quick visual checks.
When employees rely on the display name, not the sender address (or phone number), impersonation gets easier. The risk rises when finance staff handle exceptions by email with no secondary verification.
Compromised accounts change the game
Credential theft can lead to an account takeover where the attacker sends messages from a real mailbox. At that point, domain reputation and basic filtering may not help. Criminals can read threads, time their requests, and reply inside an existing conversation so the message feels familiar.
That reality is why identity controls and mailbox monitoring matter as much as email filtering.
Controls that block most BEC attempts
Reducing BEC risk does not require a full rebuild of your environment. It requires closing the gaps attackers use most often, starting with identity and then hardening email authentication and impersonation defenses.
For example, multifactor authentication (MFA) adds a second verification step so a stolen password alone cannot open an account. Conditional access can add rules based on device status, location, and sign-in risk, which helps stop suspicious logins before an attacker reaches the inbox.
Admin accounts deserve special attention. Separate privileged accounts from daily email use, limit who can grant permissions, and review access regularly. Those steps reduce the chance that one compromised login turns into broad mailbox access.
Email authentication and anti-impersonation settings
Email authentication settings help receiving systems validate who is allowed to send on behalf of a domain. Domain-based Message Authentication, Reporting, and Conformance (DMARC) is part of that control set, and it works best when paired with policies that detect lookalike domains and display-name spoofing.
Mailbox rules also need monitoring. Attackers often create hidden forwarding rules or move messages to obscure folders to avoid detection. Alerts on rule creation, forwarding changes, and unusual sign-ins give teams a chance to respond before money moves.
Strong technical controls reduce the volume of bad messages, but finance workflows are where losses are prevented.
Payment process changes that reduce loss
A BEC-resistant process assumes an inbox can lie. Finance teams should treat payment changes as a high-risk event, not a routine update.
Two-person approval for vendor bank changes and for out-of-pattern payments reduces single-point failure. Verification should happen through a known method, such as calling a stored vendor phone number or using a vendor portal, not by replying to the email that requested the change.
It also helps to define “stop and verify” triggers. Examples include new bank details, new payee names, unusual urgency, requests for secrecy, or payments outside normal amounts. These triggers give staff permission to slow the transaction and follow a checklist instead of reacting to pressure.
Building a response plan for suspicious messages
Prevention reduces risk, but teams still need a clear plan for the messages that get through. A response plan should be simple enough that employees will use it during a busy day.
Start with reporting. Staff need a single way to flag suspicious emails, and they need to know what happens next. IT should review the sender, message headers, sign-in activity, and mailbox rules, then decide whether to block the sender, reset credentials, or isolate affected accounts.
Containment steps should be written down. If a fraudulent transfer is suspected, finance should contact the bank immediately and document the timeline. If a vendor relationship is involved, notify the vendor using trusted contact information so both sides can check for compromised accounts.
Closing thoughts
BEC works because it blends into normal work and exploits trust. The most effective defense combines identity protection, email configuration, and payment verification steps that make fraud harder to complete. Those controls also improve resilience against other threats that start with email.
If your team wants to tighten defenses against email fraud, Axxys can help align controls across Microsoft 365. Contact us here today to start implementing email safety controls that will fortify your business – and your employees – from a nefarious email compromise.
