Is Your Invoice a Deepfake?
Securing Against Voice and Email Cloning
That urgent email from your Managing Director asking for a rush payment might look and sound perfect, but it could be a highly sophisticated AI deepfake.
Business email compromise cost businesses over £2 billion last year. Attackers now use AI to clone voices and write convincing emails that mimic your team's tone perfectly, making it nearly impossible to spot a fraud by sight alone.
The key is out-of-band verification. Every change to bank details or high-value payment must be confirmed via a secondary, independent channel, such as a direct phone call to a known number on file.
This process removes the burden from your staff and creates a culture where verifying requests is the standard. Your funds stay safe, regardless of how smart or convincing the AI technology becomes.
Why Accounts Payable Teams Are in the Crosshairs
Accounts payable sits at the intersection of trust and timing. Accounts teams process invoices, manage supplier details, and execute payments, often under pressure to keep operations running smoothly.
For attackers, that combination is ideal.
Most successful fraud does not involve breaking into systems. It often involves impersonation. This involves posing as a trusted position whether that be an executive, supplier or an internal colleague to then redirect payments or update bank details before anyone notices.
AI has made that impersonation dramatically more scalable.
Where it once required skill and time to craft a convincing request, tools are now widely available that automate the research, writing, and contextual tailoring that make fraud blend into normal AP workflows.
By mid-2024, an estimated 40% of BEC phishing emails were already AI-generated, with that share expected to grow significantly.
Need to find out more about AI? https://www.5cservices.co.uk/news/how-to-use-ai-for-business-productivity-while-staying-cyber-secure
1. Emails that blend into normal workflow
Traditional phishing relied on volume and imperfection. AI has changed that. Modern emails are grammatically correct and written in the specific tone of the executive or supplier being impersonated.
They reference active projects, current invoice numbers, and upcoming payment runs. For Accounts teams processing high volumes of routine communications, that level of familiarity is exactly what lowers the guard.
What AI -Enhanced Fraud Looks Like in Practice
2. Invoice and payment redirection
One of the most common Account fraud patterns involves payment redirection. Attackers may intercept a legitimate invoice exchange and quietly alter the destination account. They then send a short message claiming a supplier has updated its banking details, or re-issue a real invoice with minor modifications.
The surrounding content looks entirely legitimate because, in many cases, it is drawn from real correspondence.
3. Voice cloning and executive impersonation
Email isn’t the only channel being exploited. AI voice-cloning tools can replicate a person’s voice from a short audio sample. That makes it possible to leave convincing voicemails or place calls that sound like a known executive.
For Accounts teams accustomed to verbal approvals on high-value or urgent payments, this removes one of the few remaining verification methods that email security alone cannot address.
Why Traditional Checks No Longer Work
Security awareness training still matters, and investing in it remains worthwhile. But AI has changed what Account teams are up against. Attacks no longer contain the signals that training programs once focused on: awkward phrasing, mismatched logos, odd sender addresses, or generic greetings. Modern fraud emails can reference the recipient's organisation, active suppliers, and current invoice values drawn from publicly available or previously intercepted sources.
When a fraudulent request is indistinguishable from a legitimate one, placing the burden of detection on the Accounts team puts it in the wrong place. The organisations that reduce risk are not asking staff to be more suspicious. They are building verification processes that work independent of how a message looks.
Building Process Around the Risk
The most effective defence is not the sharper instincts. It is removing ambiguity from high -risk actions.
Out - of - band verification as standard
Any request to change supplier bank details or approve an urgent payment outside the normal cycle should require secondary confirmation through a known, independent channel — not a reply to the same email thread.
Calling a supplier on a number already on file, or confirming with a colleague directly, breaks the impersonation chain regardless of how convincing the original request appeared.
Layered access and authentication controls
Restricting access to financial systems and enforcing multi-factor authentication limits the damage a compromised account can cause.
If an attacker gains access to a vendor's email, MFA requirements on the receiving end create friction that can slow or stop a fraudulent change before any money moves.
A culture that supports slowing down.
Fraud prevention improves when staff feel safe questioning requests, including from senior leadership. A team member who pauses a payment to verify it is not being obstructive.
They are doing exactly what good process requires. Building that culture starts with leadership modelling the behaviour and making clear that slowing down on high-risk actions is always the right call.
Shift the Burden from People to Process
Concerned about AI - enhanced fraud targeting your finance teams or clients? Contact us or schedule an appointment to review your current controls and identify where the important gaps are.
Article used with permission from The Technology Press.