DATA DOCTORS

An explanation of how new credit cards have information stolen

Nov 19, 2022, 5:00 AM

Q: How can thieves steal a brand-new credit card that I’ve never used?

A: Anyone with a debit or credit card has likely experienced the unsettling notification of a fraudulent transaction that leads to questioning what they did to allow this to happen.

The natural assumption is that a recent transaction with a compromised retailer or an unscrupulous employee used a card skimmer to capture the card details.

Many retailers or restaurants are wrongly accused of being responsible for the compromise because the notification of a fraudulent transaction came right after the transaction with them.

Your situation where the card was never used clearly shows why jumping to conclusions about a recent transaction can be misguided.

Massive Guessing Attacks

There’s a form of “card cracking” that uses computers and online bots to guess your card number, expiration date, or the three-digit CVV (Card Verification Value) on the back.

Let’s start with the 16-digit card number, which may look like a complicated thing to guess, but they don’t need to guess all the numbers.

The first 6 numbers signify the card network and the issuing bank, which is clearly explained online.  Look at your credit cards and you’ll see that if it’s a Visa card, it starts with a 4. Mastercard starts with a 5 and American Express starts with a 3.Since the cyber thieves know which numbers are standard and which ones need to be guessed, they set up large online bots that can submit small transactions to thousands of e-commerce websites with the guessed numbers to see which ones are accepted.

This is why you often hear of a massive fraud incident that only targeted customers of a certain bank.

Another way they perform their guesses is by compromising a less secure credit card processing system, which gives them the ability to run thousands of transactions per second to quickly discover legitimate card numbers.

Known credit card numbers can also be purchased from the dark web to bypass the need to guess them at all.

Once they determine legitimate card numbers the rest is quite simple from a math standpoint.

The expiration date is one of the easiest to guess since the date is only up to 5 years or 60 different values. Your 3-digit CVV only has 1000 possible combinations, which is nothing when you consider bots can submit thousands of transactions in a very short period of time.

Recent Example

I recently chimed in on a news story from Arizona where a large number of Wells Fargo customers (including a close relative) were alerted to an attempt at a fraudulent transaction that had the incorrect expiration date.

A small computer shop in Alabama was used to attempt to process 560,000 transactions in the middle of the night with many of the transactions being rejected because of an incorrect expiration date.

The thieves clearly acquired a list of valid credit card numbers of Wells Fargo customers in the Phoenix area and used the credit card processor for the small shop in Alabama to execute their massive guessing scheme.Until the credit card industry changes its current methods, this very effective method of card cracking will continue to be a nuisance to us all.

Data Doctors

Many of the fake videos you’ll encounter are likely to be viewed on your smartphone, which can ma...

Data Doctors

Here are all the tips we know regarding how to spot deep fake videos

Many of the fake videos you’ll encounter are likely to be viewed on your smartphone, which can make detection a bit more difficult.

5 days ago

Patrick Mahomes #15 and head coach Andy Reid of the Kansas City Chiefs are recorded on a phone as t...

Data Doctors

Handy tech tips all Valley residents should use to find lost phones in a snap

Q: My phone went missing, and I haven’t been able to locate it using the Find My service, so what should I do next?

12 days ago

(Pexels Photo)...

Ken Colburn, Data Doctors

Here are tips for freeing up Google storage space

Google provides a generous amount of free online storage but it can fill up quickly depending on how many of its resources you use.

19 days ago

Discover how to assess, estimate, and shop for the right battery pack with this concise guide. (Pex...

Data Doctors

Here is everything you need to know for testing and buying battery banks

Discover how to assess, estimate and shop for the right battery pack with this concise guide.

26 days ago

(Pexels Photo)...

Ken Colburn, Data Doctors

Here are the truly free smartphone video editing apps

The processing power on our smartphones has grown exponentially, allowing anyone to perform sophisticated video editing easily.

1 month ago

Google Maps app....

Data Doctors

How to rediscover places visited years ago on Google maps

Whether you're an Android or iOS user, or prefer accessing Google Maps on your computer, you'll find step-by-step instructions to unlock your travel memories effortlessly.

1 month ago

Sponsored Articles

...

Collins Comfort Masters

Here’s 1 way to ensure your family is drinking safe water

Water is maybe one of the most important resources in our lives, and especially if you have kids, you want them to have access to safe water.

...

Day & Night Air Conditioning, Heating and Plumbing

Day & Night is looking for the oldest AC in the Valley

Does your air conditioner make weird noises or a burning smell when it starts? If so, you may be due for an AC unit replacement.

(KTAR News Graphic)...

Boys & Girls Clubs

KTAR launches online holiday auction benefitting Boys & Girls Clubs of the Valley

KTAR is teaming up with The Boys & Girls Clubs of the Valley for a holiday auction benefitting thousands of Valley kids.

An explanation of how new credit cards have information stolen