Card Testing Attack

What is Card Testing Attack?

A card testing attack is a type of fraud where criminals use automated scripts to verify the validity of stolen credit card numbers by making small, low-value purchases. Once a card is confirmed as active, the attacker proceeds to make much larger fraudulent transactions elsewhere.

Why It Matters

• These attacks can overwhelm a merchant’s payment gateway with a high volume of small transactions in a short period.

• Merchants may face increased processing fees and potential penalties from payment networks for high decline rates.

• Early detection of card testing helps prevent larger subsequent fraud losses and protects the merchant’s reputation.