title: "Invoice Fraud: How Criminals Redirect Your Payments and How to Stop It" date: 2026-07-24 category: Fraud / Business Email Compromise summary: The most common way small businesses lose real money, and the simple checks that prevent it before it happens. image: /assets/blog/invoice-fraud-prevention.png

tags: invoice fraud, payment fraud, BEC, business email compromise, SME security, Secure365 hashtags: #InvoiceFraud #BEC #BusinessEmailCompromise #CyberSecurity #SmallBusiness #Secure365 #FraudPrevention

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Invoice Fraud: How Criminals Redirect Your Payments and How to Stop It

ID: 2 | Category: Fraud / Business Email Compromise | Published: 2026-07-24

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Every year, small businesses across Australia lose millions of dollars to invoice fraud. Unlike phishing or ransomware attacks that grab headlines, invoice fraud operates quietly in the background, often going undetected until money has already left the building. The good news is that most successful invoice fraud schemes rely on simple tricks that can be stopped with a few basic controls and a culture of verification.

How Invoice Fraud Works

Invoice fraud typically follows one of these patterns:

1. Email Impersonation

An attacker spoofs or compromises an email account belonging to a supplier, contractor, or even a senior executive, then sends a modified invoice with updated bank details. The finance team processes the payment thinking it is legitimate.

2. Compromised Supplier Accounts

A supplier's own email is breached. The criminal uses the existing communication channel and relationship to send fraudulent invoices directly from what appears to be the trusted contact.

3. Domain Spoofing

Attackers register a domain that looks nearly identical to a real supplier or client, then send invoices from that address. A simple visual inspection can sometimes catch this, but increasingly sophisticated attacks make it harder to spot by eye alone.

4. Inbox Manipulation

Once inside a business email system, attackers may create hidden rules that archive legitimate payment confirmations while allowing fraudulent ones through, keeping the deception alive for weeks or even months.

Why Small Businesses Are Vulnerable

Small businesses are attractive targets for invoice fraud for several reasons:

  • Limited security resources – Many do not have dedicated IT or security teams
  • Email authentication gaps – Missing SPF, DKIM and DMARC records make domain spoofing easier
  • Single points of failure – Finance tasks often sit with one person without secondary verification
  • Urgency pressure – Staff are frequently told to process payments quickly, reducing the chance for a second look

Practical Steps to Stop Invoice Fraud

1. Verify Bank Details Out of Band

Never process a payment based solely on bank details received via email. Always verify new or changed bank account information through a known phone number or face-to-face conversation with your supplier or contractor.

2. Implement Dual Approval for Payments

Require two authorised people to approve any payment, especially those exceeding a set threshold. This simple control alone stops most invoice fraud attempts.

3. Enable Email Authentication (SPF, DKIM and DMARC)

These DNS records tell receiving mail servers how to verify that emails claiming to be from your domain are genuine. Without them, attackers can spoof your brand with ease.

4. Use Microsoft Defender for Office 365

Defender's impersonation protection detects when senders appear to come from within or outside your organisation but do not genuinely represent those identities. It flags suspicious emails before they reach the inbox.

5. Monitor for Malicious Inbox Rules

Periodically review mailbox rules in Outlook and Exchange Online. Attackers who gain access to a system often create forwarding or archive rules to stay hidden.

6. Train Your Team on Red Flags

Teach staff to recognise common warning signs:

  • Requests that come via email but feel unusual
  • Urgent payment requests with changed bank details
  • Invoices from suppliers they do not normally deal with
  • Slight changes in sender addresses or display names

The Role of Microsoft 365 in Prevention

Microsoft 365 provides a suite of tools that directly counter invoice fraud:

  • Defender for Office 365 – Blocks impersonation and malicious links before they arrive
  • Exchange Online Protection (EOP) – Filters spam, phishing and domain spoofing at the gateway
  • Secure Score – Tracks your email security posture and highlights gaps like missing DMARC records
  • Audit Logs – Provide visibility into who accessed what and when

Building a Fraud Resilient Culture

Technology is only part of the defence. The most effective protection comes from people who know what to look for:

  • Establish clear procedures around payment verification
  • Make staff comfortable escalating suspicious requests without fear of criticism
  • Run regular phishing simulations that include invoice fraud scenarios
  • Review and update your controls whenever new tactics emerge in the threat landscape

Final Thoughts

Invoice fraud is not a complex attack. It relies on trust, urgency and a lack of verification. By implementing straightforward controls like dual approval, email authentication and impersonation detection, most businesses can eliminate their exposure to this very common threat. The cost of prevention is negligible compared with the financial and reputational damage that comes from falling victim.

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About the Author: Jordan Gall is a cybersecurity professional specialising in Microsoft 365 security, fraud prevention and enterprise compliance.