What is invoice fraud & billing scams?

Estimated reading time
6 min

Invoice fraud occurs when a criminal modifies or fakes an invoice for you, your business, or a vendor, hoping you will mistakenly pay it.
Some of the red flags of invoice fraud include details that don’t match, such as the name on the invoice and the email address, receiving an unexpected invoice for a service you never requested, or pressure to pay the invoice immediately even if it is the first time you’ve seen it.
Help protect yourself and your business by always verifying payment and sender details, keeping your software and devices up to date, training your staff, and more.

Invoices are an integral part of managing and interacting with businesses. They help sellers keep track of sales, confirm a customer’s purchase, and ensure businesses are getting paid properly.

As we all get busier with our lives and do more of our day-to-day admin online, being vigilant and verifying the legitimacy of an invoice is increasingly essential regardless of whether we’re a business or an individual.

Scammers can capitalise on a lack of vigilance to trick you into paying a fake or modified invoice. In 2023 alone, Australians reported $16.2 million in losses from payment redirection scams, which often involved faked invoices.¹

“These cybercriminals are opportunistic,” says Victor Mangos, ANZ’s Product Area Lead in Cyberfraud. “They’ll throw out this massive net and see which businesses [or individuals] will bite. This is how scammers often get their foot in the door.”

“And at the same time,” adds Sean Byrne, an ANZ Business Manager in Cyberfraud, “once the cybercriminals realise there are high values to play with, they put in the time and effort to try and target bigger payments.”

We’re exploring some invoice fraud basics to help you protect your hard-earned money from cyber criminals.

What are invoice fraud and false billing scams?

Invoice fraud, false billing, and payment redirection scams share the same theme. At their core, these scams happen when a scammer impersonates a legitimate company that you or your business have previously dealt with and could also fall under the banner of business email compromise. The scammer might send an invoice with altered payment details from a business’ compromised email account – because someone unknowingly installed malware onto a work device. Or the scammer might send your business an email that looks like it’s from a legitimate company. So, you might pay the scammer instead of a supplier.

The scammers might gain access to a business’ system through a phishing link or remote access scam. They trick you into downloading malware, giving them access to your device, computer network, and files. They can then take their time to identify high-value invoices and wait for you to send them before they strike.

Another way these criminals run these scams is by sending an unexpected email with an invoice attached under the guise of a trusted, well-known business. The body of the email might say, ‘Your subscription is about to expire. Pay the attached invoice now to renew it for another year’, even if you didn’t sign up for the service in the first place.

3 examples of invoice fraud scams

1. An invoice is intercepted and modified

If a cybercriminal has compromised your email or the account of a business you work with, they might wait until you (or the business) send an invoice for a large sum of money.

“The cybercriminal might intercept the invoice and change the account payable details to their own,” explains Sean. “For example, if you’ve hired a builder and the scammer has compromised their email, they can use the builder’s account to intercept and modify the invoice with new payment details.”

Here’s a breakdown of how this type of invoice fraud might happen:

The scammer compromises your email system with malware, a phishing link, or a hack.
They wait for you to send an invoice to another business.
The scammer intercepts the invoice and modifies it for their own gain, such as changing the bank account number to their own or increasing the payable amount.
They forward the invoice to the other business.
The other business pays the scammer without realising what’s happened.

2. You receive an invoice for something you didn’t purchase

You might receive an email from a well-known and trusted business with an attached invoice or link (or both). The email asks you to pay, renew a subscription, or purchase a service or product. However, you never signed up to receive the business’ services, or it’s a company you rarely (if ever) engage with.

For example, you might receive a subscription renewal email from a scammer impersonating a security software company even though you never joined. Or you might receive an invoice for a purchase you never made.

3. You’re overcharged for a product or service

A business might deliberately overcharge you for a product or service, even though the initial quote is lower. They might add extra charges that weren’t outlined in the original quote, such as exaggerating the quantity of certain parts or increasing the per-unit price.

If you don’t compare the original quote to the invoiced amount, this type of fraud can be easy to fall for. For instance, a plumbing company might initially quote you $150 to fix the toilet. After the job is done and you receive the final invoice, the price has jumped to $300. The plumber claims it’s because they had to buy extra parts and spend more time than usual repairing the toilet when they really just wanted more money in their back pocket.

How can you try to spot invoice fraud?

Fake invoices can sometimes be hard to spot. Here are some invoice fraud red flags you can look for:

The email address doesn’t match the business, or it looks different from previous communications.
For example, the name of the business may say ‘ANZ’ but the email the invoice comes from is ‘a-nz.comau’. Alternatively, the legitimate email could be ‘hello@anzbank.com.au’ but the invoice is sent from ‘ hello@anz-bank.com.au’.
The payment details provided by the business don’t match previous invoices you've received or are different from the information in your system.
You receive an unexpected invoice for services you didn’t pay or sign up for. There’s a sense of urgency to pay the invoice in the email to restore your subscription or service, regardless of whether you signed up for it.
The sender pressures you to pay immediately or threatens you with legal action if you don’t comply. While a payment deadline is standard with invoices, same-day payments or threats aren’t.
There are suspicious links or attachments in the email that the sender encourages you to click on or download.

How to help protect yourself or your business from invoice fraud

Here are some simple steps you can take to help protect yourself (or your business) from false billing scams:

Compare the email and the suspected fake invoice with a genuine one. Look for any discrepancies in the message or invoice, such as variations in payment methods or banking details.
Train your staff about this type of fraud (and others), providing clear steps to avoid it.
Contact the business you’re dealing with using a phone number you have sourced independently. For example, you might have a business card, or you can search for their number online. Don’t use the contact information provided in the invoice or email.
Update all your devices and software to the latest version. This can help address weaknesses and make it harder for cybercriminals to get into your devices and accounts.
Pause before you make a payment or respond to the email. Take the time to verify the sender’s information and check that their request is legitimate.

What can you do if you or your business has been targeted by invoice fraud?

Contact your bank straight away if you have shared financial information or transferred money. If you are an ANZ customer, contact us immediately to report the fraud.
If you shared credit card details, ‘block’ or cancel those cards immediately. If your cards are with ANZ, you can report the stolen card through the ANZ app or by calling us.

Who can you contact if you’ve been targeted by invoice fraud?

Help others by reporting to Scamwatch or to the Australian Signals Directorate’s Australian Cyber Security Centre’s ReportCyber.
Contact your bank immediately if you share personal or financial information.
If you’re an ANZ customer, you can report fraud or suspicious activity in multiple ways, such as through the ANZ app or by calling us

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