Skimming
Posted on 09. Feb, 2009 by admin in Merchant Article
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 victim’s 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 a 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.
Skimming is difficult for the typical card holder to detect, but given a large enough sample, it is fairly easy for the bank to detect. The bank collects a list of all the card holders who have complained about fraudulent transactions, and then uses data mining to discover relationships among the card holders and the merchants they use. For example, if many of the customers used one particular merchant, that merchant’s terminals (devices used to authorize transactions) can be directly investigated. Sophisticated algorithms can also search for known patterns of fraud. Merchants must ensure the physical security of their terminals, and penalties for merchants can be severe in cases of compromise, ranging from large fines to complete exclusion from the merchant banking system, which can be a death blow to businesses such as restaurants which rely on credit card processing.
Carding
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 bank’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 expiry date, as well as the more prevalent use of wireless card scanners that can process transactions right away. Nowadays, carding is more typically used to verify credit card data obtained directly from the victims by skimming or phishing.
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.
Source: Wikipedia

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