Auto-Dialling Scam

What is auto-dialling fraud?

Auto-dialling fraud, sometimes called an international modem scam, was a type of telephone fraud that mainly affected internet users during the dial-up era. It worked by secretly changing how a computer connected to the internet, routing calls through expensive international phone numbers instead of local ones.

The scam made headlines in 2004 when Ireland had to block calls to 13 countries after customers received unexpectedly large phone bills. Their computers had been dialling premium rate numbers in distant locations such as Chad, Mauritania and the Cook Islands without their knowledge.

While this particular fraud is now far less common due to changes in how we access the internet, understanding how it worked can help you recognise similar tactics that criminals still use today.

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How the scam worked

The fraud relied on software that criminals managed to install on victims' computers. This software was typically bundled with other programs downloaded from the internet, often disguised as something legitimate or desirable.

Once installed, the malicious software would alter the computer's modem settings. Instead of dialling a local number to connect to your internet service provider, the modem would dial a premium rate international number. These calls could cost several pounds per minute, and a portion of that fee would be passed back to the criminals running the scam.

The victim would often have no idea anything was wrong until their phone bill arrived weeks later. By then, hours of expensive international calls could have been made, sometimes totalling hundreds or even thousands of pounds.

For the scam to work on a large scale, criminals needed to infect many computers. They often used websites offering free content, particularly adult material, as bait. Visitors would be asked to download a small program or viewer to access the content. That download contained the auto-dialler software.

Some versions of the scam were more sophisticated. They would only dial the expensive number briefly and at odd hours, making detection harder. Others would reconnect immediately if the user tried to disconnect, running up charges continuously.

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Who was at risk?

This scam could only affect computers that used a dial-up modem connected to a telephone line to access the internet. If your computer was not physically connected to a phone socket, the fraud could not work because there was no way for the software to make telephone calls.

Broadband users connecting through a router or cable modem were not vulnerable to this specific type of fraud. The shift away from dial-up internet in the UK during the mid-2000s largely eliminated the risk for most households.

However, there may still be some situations where dial-up connections are used, particularly in very rural areas or for specific legacy systems. Anyone still using a dial-up modem should be aware that this type of software could theoretically still pose a risk.

The underlying principle of the scam, secretly using your equipment to generate charges that benefit criminals, has not disappeared. Modern equivalents include malware that uses your computer to mine cryptocurrency, or fraudulent apps that send premium rate text messages from your mobile phone.

How to protect yourself

If you still use a dial-up connection, there are several steps you can take to reduce the risk of auto-dialling fraud:

• Only download software from trusted sources. Avoid programs offered by unfamiliar websites, especially those promising free access to content that would normally be paid for.
• Keep your operating system and security software up to date. Modern antivirus programs can detect many types of auto-dialler software.
• Check your phone bill regularly for unfamiliar numbers or unexpected charges. Contact your provider immediately if you spot anything suspicious.
• Ask your phone provider about international call barring. This can prevent calls to certain countries or premium rate numbers from being made on your line.
• Consider using a broadband connection if one is available in your area. This removes the dial-up vulnerability entirely.

For those using mobile phones or smartphones, similar caution applies to downloading apps. Stick to official app stores and check reviews before installing anything. Some malicious apps can send premium rate messages or make calls without your knowledge.

If you believe you have been a victim of this type of fraud, report it to Action Fraud, the UK's national reporting centre for fraud and cybercrime. You can contact them through their website or by telephone. Your phone provider may also be able to help dispute charges if you can demonstrate that calls were made without your consent.

Ofcom, the UK communications regulator, provides guidance on nuisance calls and phone fraud. Their website has information about your rights and how phone companies should handle complaints about unexpected charges.

While auto-dialling scams are largely a thing of the past for most internet users, they serve as a reminder that criminals will always look for ways to exploit technology. Staying cautious about what you download and monitoring your bills remain sound habits regardless of how you connect to the internet.

The Next Step

Now that you have read through the advice above, you might want to put it into practice. Our Scam Detector lets you got a text, call, email or offer that feels off? Paste it in below and we will tell you how scammy it looks, the warning signs to spot, and exactly what to do next. Try it now →