Carding and BIN Attacks: How Your Credit Card Is Stolen Online

In the digital age, where online transactions have become part of our daily lives, the security of payment card data is a top priority. Yet, cybercriminals are constantly refining their techniques to bypass defenses. Among the most insidious and widespread threats are carding and BIN attacks, two fraudulent methods that allow them to generate and validate credit card numbers to be used for illicit activities. Understanding how these attacks work is the first step to protecting yourself effectively and navigating the world of online shopping with greater awareness.

These practices not only cause direct financial losses to cardholders but also undermine trust in electronic payment systems and can damage the reputation of the companies involved. The phenomenon is on the rise: according to recent data, in Italy in 2023, the value of unauthorized transactions increased significantly, rising from 0.0069% in 2022 to 0.0124%. This article explores in detail the mechanics behind carding and BIN attacks, analyzing the Italian and European context and providing useful tools to recognize and prevent this type of fraud.

What Carding Is and How It Works

Carding is a criminal activity that involves illegally using stolen credit or debit card data to make unauthorized purchases. The term comes from the word “card” and originally referred to verifying the validity of a stolen card through small test transactions. Today, the concept has expanded to include the entire process, from data acquisition to its financial exploitation. The criminals, known as carders, obtain the information through various methods, including phishing, e-commerce site database breaches, or by purchasing data lists on the dark web.

Once in possession of the card numbers, expiration dates, and CVV codes, carders move on to the “testing” phase. They use automated bots to make small purchases on websites with weak security controls. If the transaction is successful, the card is confirmed as “live” and ready to be used for larger purchases, often of luxury goods or easily resold gift cards, or its data is sold on illegal markets on the dark web.

The Stages of a Carding Attack

A typical carding attack unfolds in well-defined steps, often automated to maximize efficiency. The first step is data acquisition. Criminals exploit security flaws, phishing emails, or malware to steal card information. Subsequently, this data is collected in vast archives and often sold in bulk on the dark web, where the price can vary based on the “freshness” and completeness of the information. A complete “kit” may include not only the card data but also the cardholder’s personal information, such as address and social security number, making the theft even more dangerous.

The second phase is verification, also known as card testing. To avoid being blocked, criminals use bots that attempt thousands of micro-transactions on various e-commerce sites. These charges, often for just a few cents, serve to confirm that the card is active and has not yet been blocked by the owner. Once this phase is passed, the card is ready for the final step: monetization. The validated data is used to purchase easily resalable goods or sold directly to other criminals, fueling a vast illegal ecosystem.

A Simple Explanation of a BIN Attack

A BIN attack is a more specific and technical form of fraud, closely related to carding. The name comes from Bank Identification Number (BIN), which are the first 4-8 digits of a payment card number that identify the issuing banking institution, the card type (credit, debit, prepaid), and sometimes even its tier (e.g., Gold, Platinum). In a BIN attack, criminals don’t start with already stolen card data; they generate it from scratch using brute force.

By leveraging a known BIN, fraudsters use specialized software to systematically generate all possible combinations of the remaining card numbers, expiration dates, and CVV codes. These programs can test thousands of combinations per second. The goal is to “guess” a valid combination. Once a working match is found, the criminals move on to the card testing phase, just as in traditional carding, to confirm the card’s usability before exploiting it.

The Logic Behind Number Generation

The generation of credit card numbers is not completely random. It is based on a precise structure and a validation algorithm called the Luhn algorithm (or Mod 10). This algorithm, developed in 1954, is used to validate the formal correctness of a numerical sequence and is used for most credit cards. The last digit of the card number, the so-called “check digit,” is calculated based on the other digits according to a specific mathematical formula.

Criminals exploit this logic to their advantage. Starting with a valid BIN, their software generates the missing digits and calculates the final check digit using the Luhn algorithm. In this way, they produce a large quantity of numbers that, while not necessarily associated with a real account, are formally valid and can pass an initial superficial check by a payment system. This technique, combined with the automatic generation of expiration dates and CVVs, drastically increases the chances of finding an active and vulnerable card.

The Italian and European Context: Tradition and Innovation in Defense

The European market, and the Italian one in particular, has unique characteristics that influence the spread and prevention of online fraud. On one hand, there is a strong tradition tied to security and the protection of savings, which translates into a certain caution among consumers. On the other, innovation in digital payments is advancing rapidly, driven by new consumer habits. In this scenario, criminals adapt their strategies, exploiting both technological vulnerabilities and the lesser familiarity of some users with digital tools. According to a recent report by the Bank of Italy, the fraud rate on payment cards in our country is lower than the European average, but the phenomenon is growing.

European financial institutions and law enforcement agencies actively collaborate to counter these threats. Coordinated actions, such as the “Carding Action” led by Italy in collaboration with Europol, have made it possible to analyze hundreds of thousands of credit card codes and block tens of thousands before they could be used fraudulently. This synergy between traditional investigation and technological innovation is crucial. Banks invest in advanced transaction monitoring systems capable of detecting anomalies, such as a high frequency of small transactions from the same IP address, a typical sign of a carding attack.

How to Protect Yourself from Carding and BIN Attacks

The most effective defense against this type of fraud is based on a combination of good personal practices and security tools offered by banks. Awareness is the first shield. It is crucial to learn to recognize phishing attempts, not to click on suspicious links, and never to share your card details via email or messages. For online purchases, it is always better to prefer reliable e-commerce sites that use advanced security protocols. A good tip is to use disposable virtual cards or prepaid cards with a limited balance to contain any potential damage.

From a technological standpoint, it is essential to activate all security systems offered by your bank. Two-factor authentication (2FA), for example, via an app or an SMS code, adds a crucial layer of protection, making it much harder for a criminal to authorize a transaction even if they have the card details. It is also important to enable SMS or app notification services for every transaction, so you can monitor movements in real time and immediately block the card in case of suspicious charges. Regularly checking your statement is another essential habit for promptly identifying any anomalies.

What to Do in Case of Fraud

If, despite all precautions, you discover unauthorized charges on your account, it is crucial to act quickly. The first thing to do is to immediately contact your bank or card issuer to request an immediate block on the card. This will prevent criminals from making further transactions. Most financial institutions offer a dedicated toll-free number, available 24/7, for these emergencies. Staying calm and providing all the required information clearly is essential to speed up the process.

Next, you must file a report with the competent authorities, such as the local police. The report is a fundamental document for initiating the process of disputing the fraudulent transactions and requesting a refund. You must then send a written communication to your bank to formally dispute the charges, attaching a copy of the report. Thanks to the protections provided by law, in most cases of fraud without gross negligence on the part of the holder, it is possible to obtain a full refund of the stolen amounts.

Conclusion

Carding and BIN attacks represent a real and constantly evolving threat in the digital security landscape. Cybercriminals use sophisticated technologies and user psychology to achieve their goals, generating valid credit card numbers and using them for large-scale illicit activities. However, knowledge of these techniques and the adoption of simple but effective security measures can make a big difference. Protecting your financial data is a shared responsibility: on one hand, banks and institutions must invest in increasingly advanced defense technologies; on the other, every user has a duty to be an informed and cautious digital consumer.

Monitoring your accounts, using tools like two-factor authentication and virtual cards, and acting promptly in case of suspicion are the most powerful weapons at our disposal. The culture of security, which in Italy is rooted in a traditional focus on saving, must now evolve to embrace the challenges of digital innovation. Only through a proactive and aware approach will it be possible to continue benefiting from the convenience of online payments, minimizing risks and protecting our assets in an increasingly connected world.

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