AegisAI Perspectives · 118
Business email compromise is a payment request with no link or malware, so filters pass it; the sender history and the change asked for are what catch it.
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Business email compromise is a payment or data request sent from a real or lookalike business mailbox, and the FBI's IC3 counted $3,046,598,558 in BEC losses for 20251. It is hard to detect because there is no link or malware to find19, so AegisAI reads the sender's history, the change being asked for and where the reply goes23.
The FBI's IC3 2025 Annual Report, published in April 2026, puts BEC losses at $3,046,598,558 for 2025, against $2,770,151,146 in 2024 and $2,946,830,270 in 20231. The same report counts 24,768 BEC complaints in 2025, up from 21,442 in 2024 and 21,489 in 2023. Only investment fraud, at $8,648,617,756, lost more money than BEC in 2025.
An IC3 public service announcement of 11 September 2024 counts $55,499,915,582 in exposed BEC losses across 305,033 incidents between October 2013 and December 20238.
Cite the 2025 figures with the report url, its April 2026 date and the page number, so finance can check each one.
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IC3 defines BEC by its goal: an unauthorized transfer of funds, reached by compromising email accounts and other channels such as phone numbers and virtual meeting applications, through social engineering or computer intrusion6. Traditional phishing needs the reader to click a link or open a file. A BEC message only needs the reader to act on a request, such as paying an open invoice into a new account, and there is no link or malware to find.
BEC types, from invoice fraud to payroll redirects, are listed with a layered prevention checklist in how to prevent business email compromise.
Sort each suspicious message by the action it asks for, not by whether it carries a link or a file.
A gateway's link and attachment checks inspect the payload, and a BEC message has none. Sender authentication does not close the gap either: a hijacked vendor mailbox signs as itself, so it passes all three sender checks18.
Microsoft states that impersonation can pass the three checks (SPF, DKIM, DMARC) when the attacker created a lookalike domain and published valid DNS records11. Such a domain is registered and has its authentication records configured; only its intent, to deceive the recipient, is wrong.
Composite authentication combines the three results into a single verdict15, and even a composite failure does not directly block a message.
List the checks your filter runs, and mark each one a hijacked vendor mailbox would pass.
IC3 notes that chat generators can quickly create official-sounding emails that mimic a company's CEO, that voice cloning can be used to request a wire payment, and that not all BEC tactics are AI-enabled5. In 2025, businesses reported losses over $30 million to BEC scams involving AI.
In the State of the AI Threat in Email: 2025 report, drawn from more than 20,000 phishing emails, 50.3% of AI-generated phishing bypassed the built-in Gmail and Microsoft filters, against 28.5% of human-written phishing25.
Stop treating clean grammar and a familiar writing style as evidence that a payment request is genuine.
In vendor email compromise the request comes from the supplier's own account, so it carries the thread's real history and passes authentication. How attackers take over a supplier mailbox and wait inside real threads is set out in what is vendor email compromise and how do attackers carry it out. Multi-channel lures add the phone and the video call: IC3's definition names phone numbers and virtual meeting applications as BEC channels, and its AI section names voice cloning as a way to request a wire.
Verification by a second channel stops the payment. In April 2025 a city government office in Oregon reported a BEC loss of over $6 million; because the recipient account was already frozen, the banks checked the wire instructions and found them fraudulent; the originating bank then recalled the $6 million wire7. IC3 advises using secondary channels or two-factor authentication to verify requests for changes in account information9.
Call the vendor on the number already in the vendor file before any bank detail change is paid.
Signatures match known bad content, and a BEC message carries none, so detection has to judge the request against the relationship. Mailbox intelligence, for example, uses AI to learn each user's email patterns with frequent contacts14. Run a suspicious payment request through these seven checks in order.
Write down the change being asked for: a new bank account, a payroll redirect or a wire, as the analyst reading of the thread does.
Count earlier bank detail changes from this sender; a first change in a long thread is a signal on its own.
Compare the Reply-To domain with the From domain, since the reply destination is one of the three things to read.
Authentication is one input, never the verdict10, because a lookalike domain with valid DNS records passes it.
Compare the sending and reply domains with the vendor's real domain, letter by letter, because a registered lookalike looks legitimate.
Call the requester on a number already on file before any change is made.
Attach the thread and its headers to the ticket with the verdict reason, so both teams review one record.
Run these seven checks on the last bank detail change your finance team received.
Score your current stack on each row against a payloadless request from a hijacked vendor mailbox.
| Check | What a payloadless BEC email shows it | AegisAI |
|---|---|---|
| Link and attachment scanning | Nothing to inspect: no link or malware | The verdict rests on the sender's history and the request |
| Sender authentication (SPF, DKIM, DMARC) | Passes on a hijacked vendor mailbox or a lookalike with valid DNS records | Authentication is one input, never the verdict |
| Reply destination | Composite authentication scores the sender checks only | Reads where the reply actually goes |
| Speed and removal | A composite failure does not directly block | Median verdict 1.9 seconds, then removal from every mailbox |
| Bank detail change by phone | IC3 advises a second channel | No edge. A call to a number on file is a process control outside any mail tool |
The last row gives no tool an edge, because the second-channel check IC3 advises happens outside email. Score your current filter on all six rows before your next renewal.
AegisAI reads the thread the way an analyst would: the sender's history, the change being asked for, and where the reply actually goes. A hijacked vendor mailbox signs as itself, so SPF, DKIM and DMARC pass. The verdict rests on what this sender has sent you before and on the request itself. The median verdict takes 1.9 seconds, then the email is removed from every mailbox that received it. Run AegisAI in monitoring mode on live mail with no MX change, then turn on removal24.
Illustrative example, figures are fictional: Harlow Components (fictional) has 600 mailboxes and pays a supplier through a thread of 140 messages over two years, with no earlier bank change. On a Tuesday, a reply from the supplier's real mailbox asks accounts payable to pay invoice 7731, for $48,200, into a new account before Friday, with Reply-To set to a domain registered four days earlier. All three sender checks pass, because the supplier's mailbox signs as itself. The filter finds no link or attachment. Three signals flag it: the first bank change in 140 messages, replies routed to a four-day-old lookalike domain, and a deadline on an open invoice. Accounts payable calls the supplier on the number in the vendor file, as IC3 advises. The supplier confirms it made no change.
Replace each fictional figure with one from your own last bank change request and run the same three signals.
Track three numbers for 30 days, each in a system you already run.
An eight-step control plan, from phishing-resistant MFA to the call-back rule, is in how do you stop business email compromise. Put the three figures in front of finance and security on day 30 and set the next quarter's target from them.
IC3 defines BEC as fraud that compromises email accounts, phone numbers or virtual meeting applications, through social engineering or computer intrusion, to make an unauthorized transfer of funds. IC3 counted 24,768 BEC complaints in 2025.
The message carries no link or malware, and a hijacked vendor mailbox passes every sender authentication check. Detection has to judge the request against the sender's history instead.
No. A hijacked mailbox signs as itself, and Microsoft states that a lookalike domain with valid DNS records can pass SPF, DKIM and DMARC.
The FBI's IC3 2025 Annual Report, published in April 2026, puts BEC losses at $3,046,598,558 for 2025, second only to investment fraud.
IC3 says chat generators can write official-sounding emails that mimic a CEO, and voice cloning can request wire payments. Businesses reported losses over $30 million to BEC scams involving AI in 2025.
Use a second channel: IC3 advises secondary channels or two-factor authentication to verify requests for changes in account information. Call a number already on file, never one given in the email.
