How Skimming and Shimming Help Fraudsters Steal Bank Card Data

The bank card has long become a familiar tool for payments. The convenience and speed of payments come with potential threats. Among the most common methods of information theft are bank card skimming and shimming fraud. These schemes do not require access to a smartphone or interaction with the owner — data is read covertly during a regular transaction.

Visually, everything looks standard: the card is inserted into the terminal, the PIN code is entered, and the transaction is completed. However, in reality, the reading device has already intercepted the data and transferred it to fraudsters. A card clone can be created and used within a few hours. To avoid encountering this type of financial fraud, it is important to understand how these schemes work and how they differ from each other.

How Skimming Works: Simple Technology with Serious Consequences

Skimming is the installation of external equipment on an ATM or terminal. Most often, it is an overlay on the card reader that reads data from the magnetic strip. In addition, a miniature camera or fake keyboard may be used to capture the PIN code.

The equipment used in skimming is disguised as original ATM elements. The irregularities in the construction are not obvious: the slot is slightly wider, the keyboard is slightly thicker. Externally, everything looks quite normal, so most people do not notice the substitution.

A copy of the card is created based on the data obtained from the magnetic strip. With the PIN code, fraudsters gain access to funds, and the owner may only find out after funds are withdrawn or the card is blocked. Protection against such schemes is complicated by the fact that skimming is possible even with a single use of the card in a compromised device.

Shimming: A More Covert Threat Targeting Chips

Unlike skimming, shimming fraud involves installing a device not outside but inside the card reader. A thin board is used, which is placed between the card chip and the terminal contacts. It discreetly intercepts data at the moment of transaction.

The feature of shimming is the ability to read information even from the chip. Despite a higher level of protection, transaction data and authorization codes can be captured. This opens access to funds, especially if an outdated security system is used on the bank's side.

Shimming is difficult to detect visually. The device inside the terminal does not change the external appearance. Therefore, the only way to protect yourself is to limit the use of the card to verified places, especially when performing transactions that involve physically inserting the card into the slot.

Signs of Fraud: What Should Raise Suspicions

Fraudulent devices are difficult to notice, but in most cases, slight external signs remain. Attention to details when using terminals is an important element of bank card protection. What to look out for:

• the ATM looks unusual: there are protruding or poorly secured elements;
• the card is inserted with effort or returned with a delay;
• the keyboard is thickened, shifted, or presses uncertainly;
• holes resembling camera lenses are found in the body;
• the ATM logo or marking is carelessly applied or missing altogether.

These signs indicate the possible installation of additional reading elements. Suspicious positioning of the device (isolated place, lack of video surveillance) also increases the likelihood of fraudster interference.

If the slightest suspicion arises, the operation should be stopped. It is safer to use another ATM or payment method. Regular inspection of terminals before use is a simple but effective prevention of card data theft.

Protection Methods: What Really Works

Fraudsters use various methods, but against basic caution and digital tools, many of them become useless. Information protection begins with controlling actions related to the physical use of the card and its PIN code.

To reduce risks, it is recommended to:

1. Always inspect the ATM or terminal for suspicious elements;
2. Cover the keyboard with your hand while entering the PIN code;
3. Disable the ability to perform transactions via the magnetic strip if the bank allows it;
4. Enable SMS or push notifications for every transaction;
5. Set limits on cash withdrawals and cashless transactions;
6. Use contactless chip payments (NFC) without inserting the card into the device;
7. Immediately block the card when suspicious transactions occur.

These measures form the basic protection of bank cards and complicate the implementation of fraudulent schemes. It is especially important to remember how to protect the PIN code, as its interception is the main element in most card attacks.