Effective fraud prevention with the BIN attack score

“It all happened so fast,” says Elena, a freelance designer from Berlin. “I got a call from what looked like my bank’s number. The voice on the other end was calm, professional, and even knew the last four digits of my card. They said there was a suspicious charge and needed to verify my card details to block the transaction.”

Reluctantly, Elena confirmed her card number. Within minutes, her account had been drained through a series of small but rapid transactions—none of which she had authorized.

“I thought I was being careful,” she admits. “But they were one step ahead.”

Elena’s story is not unique. It’s one of thousands of modern fraud cases where scammers use stolen credentials, social engineering, and even synthetic identities to perform unauthorized digital transactions, often before banks can detect the breach.

Globally, the financial impact of fraud was estimated at over $485 billion in 2024, reflecting the scale of the threat and how quickly fraudsters adapt to outpace traditional security methods.

From phishing scams to card-not-present attacks, criminals use increasingly sophisticated tactics to exploit weaknesses in the digital payment ecosystem. Even more concerning is how fast these attacks happen, often completed within minutes before users or banks can respond.

Among the most dangerous and rapidly evolving forms of fraud are BIN attacks, in which criminals systematically test stolen card numbers via small online transactions to identify valid ones. While a single test transaction might appear harmless, collectively, they provide fraudsters with the data they need to carry out large-scale, high-value fraud across the payments ecosystem. Some estimates suggest the technique is so successful that fraudsters can use it to identify up to 4,800 valid card details per day.

Traditional fraud detection systems often struggle with these attacks because each transaction appears legitimate in isolation. When fraud patterns are identified, valid card numbers may be exposed, accounts compromised, and significant operational costs incurred, including large-scale card replacement and customer communication efforts.

G+D Netcetera’s 3D Secure Issuer Service offers built-in BIN attack detection and prevention to close a critical gap with fraud defence. It automatically analyses and scores every transaction in real time. When a suspicious pattern is detected, it triggers an immediate, automated response, stopping the attack before damage is done.

The BIN Attack Score solution is fully integrated with G+D Netcetera’s 3-D Secure Issuer Service, which already meets the highest security standards, including all requirements and certifications of EMVCo®, American Express®, Diners Club, Discover, JCB, Mastercard®, Union Pay, and Visa. It authenticates cardholders on behalf of over 1000 banks and card issuers during online payments. This integration allows the system to leverage existing infrastructure while adding powerful new capabilities for financial crime prevention.In addition, it ensures you can deploy the solution quickly and efficiently, leveraging their existing investment in G+D Netcetera’s services while adding powerful new capabilities for financial crime prevention.

Real-time protection, 24/7
No more relying on manual intervention or night shift monitoring. The system runs automatically around the clock, preventing information leakage and providing constant protection without extra staffing.

Avoid costly card replacements and customer disruption
Instead of replacing thousands of potentially compromised cards after an attack, our solution prevents card data from being exposed in the first place, saving your operations time, money, and reputational damage.

Preserve customer trust
Your customers expect their payment experience to be smooth and secure. By preventing fraud without affecting legitimate transactions, you protect their trust and eliminate the frustration of declined payments or card cancellations.

Reduce call center overload
Stopping attacks early prevents the flood of concerned customer calls and authentication issues that typically follow a fraud wave.

Bringing in more value for your business is the post-attack intelligence report that helps you in long-term prevention.

Meeting regulatory requirements

By providing a robust defence against BIN attacks, the solution helps institutions comply with regulations such as PSD2, which mandates strong customer authentication and fraud monitoring. Its ability to operate within the existing 3-D Secure framework ensures it meets all relevant industry standards and certifications, including PCI DSS and PCI 3DS compliance.

Future development and industry impact

G+D Netcetera continues to invest in enhancing the BIN Attack Score solution, with ongoing development focused on improving detection accuracy, expanding coverage to new attack vectors, and integrating with additional fraud prevention tools.

The solution's impact extends beyond individual financial institutions to the broader e-commerce ecosystem. By making BIN attacks less effective, the solution helps reduce the overall incentive for card testing, potentially reducing related fraud activities across the industry.

As the first provider worldwide to be certified for the latest EMV 3DS 2.3.1 protocol, G+D Netcetera continues demonstrating its leadership in payment security innovation.

A BIN attack (or BIN enumeration) is a type of credit card fraud where fraudsters attempt to identify valid card number, expiry date and CVV combinations by testing thousands of generated card details against online merchants.

Once a match is made, the attacker will either use the validated card details to make fraudulent purchases or sell the details on dark web marketplaces.

It’s called a BIN attack because the Bank Identification Number (the first six to eight digits of card numbers that identify the issuing bank) is specifically targeted. Instead of randomly guessing card numbers, they focus their efforts on a bank’s specific BIN ranges.

The process of testing card combinations is fully automated, since manually typing in thousands of card details would be inefficiently slow. Instead, fraudsters use software scripts that can test hundreds of card combinations per minute, with some attacks involving thousands of attempts per day.

A BIN attack follows a systematic process that makes them particularly effective against card issuers:

1. Target selection: Fraudsters choose a BIN range based on factors like a bank’s size, customer base or perceived security weaknesses. They’ll often target multiple banks at once.
2. Card number generation: Using publicly available BIN ranges, they’ll use automated software to generate thousands of possible card numbers.
3. Rapid testing: The generated numbers are tested against online merchants using automated software, typically with very small transactions under €1 to avoid fraud alerts. They can test hundreds of combinations per minute.
4. Validation and exploitation: If a transaction succeeds, the fraudster will quickly record the validated data (card number, expiry date and CVV code) before using the cards for larger fraudulent purchases.
5. Monetisation: Valid card details will either be used immediately to make fraudulent purchases or sold on dark web marketplaces before each card is detected and blocked.

Because the process is so highly automated, fraudsters can target thousands of cards per day. The speed of the attack and the small initial purchase value can make BIN attacks difficult to detect.

BIN attacks can hit banks particularly hard because they have to deal with both short-term and long-term impacts.

While other types of fraud also impact payment service providers (PSPs) or merchants, BIN attacks directly impact banks and their customers.

Key impacts include:

• Direct financial losses: Banks are responsible for refunding fraudulent payments to customers, even before detecting the attack. This can be expensive, with fraudulent transactions totalling €633 million in the first half of 2023 in the EU.
• Growing operational costs: To protect customers against BIN attacks, banks must invest in investigation, account blocking, card reissuing, customer service calls and fraud team resources.
• Reputational damage: Successful BIN attacks can damage customer trust, even when the fraudulent charges are redundant. And widespread news coverage of attacks can result in customers switching to competitors that they perceive as being more secure.
• Increased regulatory pressure: PSD2 proves fraud can be lowered by authenticating transactions. So regulators expect strong fraud prevention to be in place. Repeated attacks can initiate regulator reviews and hefty fines.

There are lots of ways to protect customers from BIN attacks, and a multi-layered approach should be effective.

Modern security technology like 3D Secure which uses Access Control Servers (ACS) to authenticate genuine transactions are very effective at detecting and stopping BIN fraud - fraud rates are ten times higher outside the EEA where SCA isn’t required.

Prevention methods include:

• Real-time monitoring and pattern recognition: Detect suspicious activity like multiple low-value transactions, high decline rates, multiple CVV code denials or rapid-fire attempts from the same IP addresses.
• Velocity controls and rate limiting: Limit transaction attempts from single merchants within specific time periods. This will slow down the speed that BIN attacks rely on.
• CAPTCHA and device fingerprinting: Block automated bot activity with challenges and device fingerprinting to identify bots and stop automated scripts from completing merchant checkout pages.
• Account number randomisation: Randomise account numbers and expiry dates as they’re issued to make it harder for BIN attack algorithms to detect logical patterns.
• Strong Customer Authentication (SCA): Trigger biometric authentication or mobile app confirmation when suspicious activity’s detected - institutions using EMV 3DS with one-time passcodes (OTP) can reduce fraud by up to six times.
• Shared intelligence: Share BIN attack threat intelligence with other banks and payment networks to stay up to date with attack methods.

If you’re concerned about BIN attacks affecting your bank and customers, G+D Netcetera can provide the holistic fraud prevention technology your bank needs to defend against them.

We’ve been protecting banks against credit card fraud for several decades. And our 3D Secure Issuer Service includes BIN attack detection and prevention capabilities.

Our ACS solution works with your existing payment system, and it scales efficiently as your transaction volumes grow.

With over 1000 successful bank deployments and a 9-week implementation time, we’re regularly chosen by banks and other card issuers to deliver compliant fraud-detection solutions that strengthen security while maintaining an excellent user experience.

Our PCI-DSS certified infrastructure keeps everything secure and compliant, and our dedicated client support teams are available 24/7 throughout the implementation and beyond.

Want to learn how G+D Netcetera can help defend your bank from BIN attacks? Get in touch with our experts.