Credit Card Fraud
Credit card fraud is a wide-ranging term for theft and fraud committed using a credit card or any similar payment mechanism as a fraudulent source of funds in a transaction. The purpose may be to obtain goods without paying, or to obtain unauthorized funds from an account. Credit card fraud is also an adjunct to identity theft. According to the Federal Trade Commission, while identity theft had been holding steady for the last few years, it saw a 21 percent increase in 2008. However, credit card fraud, that crime which most people associate with ID theft, decreased as a percentage of all ID theft complaints for the sixth year in a row.
When a credit card is lost or stolen, it remains usable until the holder notifies the issuer that the card is lost. Most issuers have free 24-hour telephone numbers to encourage prompt reporting. Still, it is possible for a thief to make unauthorized purchases on a card until it is canceled. Without other security measures, a thief could potentially purchase thousands of dollars in merchandise or services before the cardholder or the card issuer realize that the card is in the wrong hands.
The only common security measure on all cards is a signature panel, but signatures are relatively easy to forge. Some merchants will demand to see a picture ID, such as a driver's license, to verify the identity of the purchaser, and some credit cards include the holder's picture on the card itself. However, the card holder has a right to refuse to show additional verification, and asking for such verification is usually a violation of the merchant's agreement with the credit card companies. Self-serve payment systems (gas stations, kiosks, etc.) are common targets for stolen cards, as there is no way to verify the card holder's identity. A common countermeasure is to require the user to key in some identifying information, such as the user's ZIP or postal code. This method may deter casual theft of a card found alone, but if the card holder's wallet is stolen, it may be trivial for the thief to deduce the information by looking at other items in the wallet. For instance, a U.S. driver license commonly has the holder's home address and ZIP code printed on it.
Card issuers have several countermeasures, including sophisticated software that can, before a transaction is authorized, estimate the probability of fraud. For example, a large transaction occurring a great distance from the cardholder's home might seem suspicious. The merchant may be instructed to call the card issuer for verification, or to decline the transaction, or even to hold the card and refuse to return it to the customer. The customer must contact the issuer and prove who they are to get their card back (if it is not fraud and they are actually buying a product).
Card account information is stored in a number of formats. Account numbers are often embossed or imprinted on the card, and a magnetic stripe on the back contains the data in machine readable format. Fields can vary, but the most common include:
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- Name of card holder
- Account number
- Expiration date
- Verification / CVV code
Card Not Present
The mail and the Internet are major routes for fraud against merchants who sell and ship products, and affects legitimate mail-order and Internet merchants. If the card is not physically present (called CNP, card not present) the merchant must rely on the holder (or someone purporting to be so) presenting the information indirectly, whether by mail, telephone or over the Internet. While there are safeguards to this, it is still more risky than presenting in person, and indeed card issuers tend to charge a greater transaction rate for CNP, because of the greater risk.
It is difficult for a merchant to verify that the actual cardholder is indeed authorising the purchase. Shipping companies can guarantee delivery to a location, but they are not required to check identification and they are usually not involved in processing payments for the merchandise. A common recent preventive measure for merchants is to allow shipment only to an address approved by the cardholder, and merchant banking systems offer simple methods of verifying this information. Before this and similar countermeasures were introduced, mail order carding was rampant as early as 1992. A carder would obtain the credit card information for a local resident and then intercept delivery of the illegitimately purchased merchandise at the shipping address, often by staking out the porch of the residence.
Small transactions generally undergo less scrutiny, and are less likely to be investigated by either the card issuer or the merchant. CNP merchants must take extra precaution against fraud exposure and associated losses, and they pay higher rates for the privilege of accepting cards. Fraudsters bet on the fact that many fraud prevention features are not used for small transactions.
Merchant associations have developed some prevention measures, such as single use card numbers, but these have not met with much success. Customers expect to be able to use their credit card without any hassles, and have little incentive to pursue additional security due to laws limiting customer liability in the event of fraud. Merchants can implement these prevention measures but risk losing business if the customer chooses not to use the measures.
Identity theft can be divided into two broad categories: Application fraud and account takeover.
Application fraud happens when a criminal uses stolen or fake documents to open an account in someone else's name. Criminals may try to steal documents such as utility bills and bank statements to build up useful personal information. Or they may create counterfeit documents.
Account takeover happens when a criminal tries to take over another person's account, first by gathering information about the intended victim, then contacting their card issuer masquerading as the genuine cardholder, and asking for mail to be redirected to a new address. The criminal then reports the card lost and asks for a replacement to be sent.
Some merchants added a new practice to protect their consumers and their own reputation, where they ask the buyer to send a photocopy of the physical card and statement to ensure the legitimate usage of a card.
Skimming is the theft of credit card information used in an otherwise legitimate transaction. It is typically an "inside job" by a dishonest employee of a legitimate merchant. The thief can procure a victim’s credit card number using basic methods such as photocopying receipts or more advanced methods such as using a small electronic device (skimmer) to swipe and store hundreds of victims’ credit card numbers. Common scenarios for skimming are restaurants or bars where the skimmer has possession of the victim's credit card out of their immediate view. The thief may also use a small keypad to unobtrusively transcribe the 3 or 4 digit Card Security Code which is not present on the magnetic strip.
Instances of skimming have been reported where the perpetrator has put a device over the card slot of an ATM (automated teller machine), which reads the magnetic strip as the user unknowingly passes their card through it. These devices are often used in conjunction with a pinhole camera to read the user's PIN at the same time. This method is being used very frequently in many parts of the world. Another technique used is a keypad overlay that matches up with the buttons of the legitimate keypad below it and presses them when operated, but records or transmits the keylog of the PIN number entered by wireless. The device or group of devices illicitly installed on an ATM are also colloquially known as a "skimmer". Recently-made ATMs now often run a picture of what the slot and keypad are supposed to look like as a background, so that consumers can identify foreign devices attached.
Skimming is difficult for the typical cardholder to detect, but given a large enough sample, it is fairly easy for the card issuer to detect. The issuer collects a list of all the cardholders who have complained about fraudulent transactions, and then uses data mining to discover relationships among them and the merchants they use. For example, if many of the cardholders use a particular merchant, that merchant can be directly investigated. Sophisticated algorithms can also search for patterns of fraud. Merchants must ensure the physical security of their terminals, and penalties for merchants can be severe if they are compromised, ranging from large fines by the issuer to complete exclusion from the system, which can be a death blow to businesses such as restaurants where credit card transactions are the norm.
Carding is a term used for a process to verify the validity of stolen card data. The thief presents the card information on a website that has real-time transaction processing. If the card is processed successfully, the thief knows that the card is still good. The specific item purchased is immaterial, and the thief does not need to purchase an actual product; a Web site subscription or charitable donation would be sufficient. The purchase is usually for a small monetary amount, both to avoid using the card's credit limit, and also to avoid attracting the card issuer's attention. A website known to be susceptible to carding is known as a cardable website.
In the past, carders used computer programs called "generators" to produce a sequence of credit card numbers, and then test them to see which were valid accounts. Another variation would be to take false card numbers to a location that does not immediately process card numbers, such as a trade show or special event. However, this process is no longer viable due to widespread requirement by Internet credit card processing systems for additional data such as the billing address, the 3 to 4 digit Card Security Code and/or the card's expiration date, as well as the more prevalent use of wireless card scanners that can process transactions right away.
A set of credit card details that has been verified in this way is known in fraud circles as a phish. A carder will typically sell data files of the phish to other individuals who will carry out the actual fraud. Market price for a phish ranges from US $1.00 to US$50.00 depending on the type of card, freshness of the data and credit status of the victim.
Credit cards are produced in BIN ranges. Where an issuer does not use random generation of the card number, it is possible for an attacker to obtain one good card number and generate valid card numbers by changing the last four numbers using a generator. The expiry date of these cards would most likely be the same as the good card