A video call full of colleagues
In early 2024, a finance employee in the Hong Kong office of Arup, the British engineering firm, received a message that appeared to come from the company's UK-based chief financial officer about a confidential transaction. He was suspicious at first and thought it might be phishing. Then he joined a video call on which the CFO and several colleagues he recognized appeared to be present. They were deepfakes. He went on to make 15 transfers totaling HK$200 million, about US$25.6 million, to five bank accounts in Hong Kong. The fraud came to light when he checked with the company's headquarters.
Arup confirmed in May 2024 that it was the company involved and that it had notified Hong Kong police in January. It told CNN that "fake voices and images were used." In a statement reported by Dezeen, it said that "none of our internal systems were compromised."
Nothing was breached at Arup
That last sentence is the lesson. No firewall failed and no password leaked. What failed was a process that accepted a face and a voice as proof of authority. Every finance team has that process, written or not, and generative AI has made faces and voices cheap to imitate.
The defense, then, is not better detection. Spotting a good deepfake on a live call is unreliable, and asking a clerk to judge one puts the decision on the person under the most pressure. The defense is a rule that makes the question irrelevant: no voice, face or message authorizes a payment by itself, however senior it appears.
What FinCEN and the FBI say
FinCEN's alert FIN-2024-Alert004, issued November 13, 2024, is addressed to banks and other financial institutions and deals mainly with deepfake identity documents used to open accounts. It also notes that criminals have reportedly used generative AI to impersonate an executive or other trusted employee and instruct victims to send large sums to accounts the scammers control, and it cites press coverage of the Hong Kong case. Two of its points carry over to an AP desk. It lists multifactor authentication and live verification checks among useful practices. And it treats a counterpart who tries to change communication methods during a verification, citing technical glitches, as a red flag.
The FBI's public service announcement of December 3, 2024 (I-120324-PSA) warns that criminals generate video for real-time chats with alleged company executives. It advises verifying a caller by hanging up, researching the organization's contact details yourself and calling that number directly. It also recommends a secret word or phrase among family members. The same idea works inside a company.
The numbers are still modest. In the AFP's 2026 Payments Fraud and Control Survey, 7% of organizations that experienced payments fraud in 2025 reported a deepfake attempt. The FBI's 2025 IC3 report records more than $30 million in reported business email compromise losses involving AI in 2025, and its definition of business email compromise covers compromised phone numbers and virtual meeting applications as well as email.
Treat voice and video as untrusted
Divide channels into two groups and write the groups into policy.
Untrusted for authorization: email, text, chat and collaboration apps, voicemail, inbound phone calls and video calls, including calls where every face is familiar. A request that arrives on any of these is a request, nothing more.
Trusted for authorization: the approval workflow in your ERP or AP system, dual release in the bank portal, and an outbound call that you place to a number taken from your own records.
The test is who chose the channel. If the requester chose it, it is untrusted.
The protocol accounts payable can adopt
Adapt the thresholds to your payment sizes. Keep the structure.
1. Scope
The protocol applies to any request to make a payment, change payment details, release a payment early or skip a step, from anyone inside or outside the company, including the CEO and the CFO.
2. The callback rule
Before acting on any request in tier 2 or tier 3 below, the person processing it places an outbound call using the number in the internal directory or the vendor master. Never use a number from the message, an email signature or caller ID. Record the number called, the time, the person reached and what they confirmed. In the AFP survey, 94% of organizations verified transfer requests by calling an authorized contact at a number from official records, and 63% of those rated the practice very effective. It works when it is done exactly. It fails when someone calls the number in the email.
3. Code phrases
Each executive who may request payments outside the normal workflow holds a code phrase, agreed in person, stored offline and changed every quarter. The verifier asks for it during the callback. It is never written in email or chat and never given on an inbound call. A code phrase adds to the callback and never replaces it. Only 42% of organizations in the AFP survey used passcodes known only to both parties to a wire, though 52% of those rated them very effective.
4. Dual release tiers
| Tier | Applies to | Verification | Release in the bank |
|---|---|---|---|
| 1 | Up to $10,000 to an existing payee with unchanged details, inside the normal workflow | Workflow approval | Two people: one builds, one releases |
| 2 | $10,000 to $100,000, or any new payee | Callback to a number on file | Two releasers, neither of them the requester |
| 3 | Above $100,000, any international wire, or any request that is urgent, confidential or outside the workflow | Callback and code phrase | Two releasers, one an officer not named in the request; release the next business day unless two officers confirm |
5. Escalation triggers
Any one of these moves a request to tier 3, whatever the amount: secrecy, urgency, a request to keep colleagues out of the loop, a request to switch channels, a convenient technical problem with audio or video, a new bank account, or an account in a new country.
6. Authority to pause
Every person in AP has written authority to pause any payment pending verification, without penalty. The CEO and the CFO sign the protocol to confirm they will never ask anyone to skip it. A clerk who delays a genuine executive request for an hour is doing the job.
7. If money has moved
Call the bank's fraud line at once and ask for a recall, then file a complaint at ic3.gov with full transaction details. The FBI's guidance is that time is of the essence. Preserve the messages, call logs and meeting invitations.
Practice before it is real
Drill the protocol twice a year with a simulated request from a senior name, ideally by voice. Measure two things: whether the callback went to the right number and whether anyone asked for the code phrase. Review every exception, including genuine urgent requests, because those are the ones that teach people to skip steps. Drills built on your own approval chain and payment sizes teach more than generic awareness content, which is how payment-fraud drills in a training program are designed.
Where to start
Write the two channel lists and the tier table this week, and have the CEO and the CFO sign the protocol before anything else changes. Then check that your bank portal enforces dual release at the tiers you chose. Requests to change a vendor's bank details follow the same logic, and five controls for vendor bank-change fraud sets out that workflow. To review the payment chain, bank settings and drills together, see payment fraud defense.