American Express card used fraudulently - questions

thesaver79

Hi all,

I have just found out that one of my credit cards has been used fraudulently for online transactions.

It's a card I hardly ever use and Amex have assured that the magnetic strip hasn't been cloned.

They claim that hackers have ways of using algorithms to guess credit card numbers and security codes. Given that often websites don't ask for or validate the name on the credit card or the address, some purchases can still go through.

Does this correspond to reality? Or do I have to think that somebody has actually got the credit card out of my wallet and seen it?

Is it something that can happen any day to anybody regardless of how careful you are?

reclusive46

Its pretty much impossible to know how the card details were compromised. I wouldn't worry it about it much unless your other cards are fraudulently used.

thesaver79

reclusive46 wrote: »

Its pretty much impossible to know how the card details were compromised. I wouldn't worry it about it much unless your other cards are fraudulently used.

Does it mean that it's true that they could just guess the credit card number and security code?

I haven't found any suspicious transactions in any of my other cards, but I'm simply worrying that if someone had a chance to oversee the details of this one, they could've seen another one too.

*Scarlett

This happened to me on a card that I virtually never use. A charge of $4 appeared from California (I wish I had been lucky enough to be there).

The c/c company refunded the charge and issued a new card but they were unable to offer any explanation as to how this had happened. I don't use this card online, etc.

They did say that a small amount charged to the card will let the prospective thief know that the card is active so always keep a sharp eye on statements.

thesaver79

*Scarlett wrote: »

This happened to me on a card that I virtually never use. A charge of $4 appeared from California (I wish I had been lucky enough to be there).

The c/c company refunded the charge and issued a new card but they were unable to offer any explanation as to how this had happened. I don't use this card online, etc.

They did say that a small amount charged to the card will let the prospective thief know that the card is active so always keep a sharp eye on statements.

Yes, apparently in my statement there is one (or more) initial transaction for a small amount. After that there are several ones to buy flight tickets on various airlines' websites.

Eonel

My Amex was fraudulently used several years ago. An initial small transaction ( to check the the cloned card works ) & then it went ballistic hitting 6 US states & most of the Caribbean at the same time. Nike shops were a particular favourite.

£11k in total, but all immediately refunded by Amex.

thesaver79

Eonel wrote: »

My Amex was fraudulently used several years ago. An initial small transaction ( to check the the cloned card works ) & then it went ballistic hitting 6 US states & most of the Caribbean at the same time. Nike shops were a particular favourite.

£11k in total, but all immediately refunded by Amex.

Did you ever manage to find out how that could've happened?

Eonel

thesaver79 wrote: »

Did you ever manage to find out how that could've happened?

My money was refunded so quickly with no questions asked that I never felt the need.

My understanding is that the card was physically cloned and used in collusion with corrupt shop employees in places such as the Nike shop in the Dominican Republic.

It was clearly a very organised operation, to be cloned & appear in so many places at the same time. This happened before Chip 'n Pin was widespread.

InsideInsurance

The first 6 digits of a credit card identify the card issuer/ scheme and so there is a finite list of them. The last 2 digits are a calculated value based on the rest of the number as a checksum.

If you take a normal credit card then, 6 digits you can pick based on who you want to target, you then randomise 8 digits and use an algorithm to calculate the final two and bobs your uncle you have what is a valid card number (but no way of knowing if it has actually ever been issued to anyone)

There is no actual requirement to check anything when taking card payments from people in terms of AVS (address validation service), CCV (security number), expiry date etc but the less security checks the merchant does the lower the transaction fee they pay - there is no system for checking card name that I am aware of (in the UK at least)

I thought the CCV was randomly generated and therefore cannot be "calculated" but it wasnt a security check back when I did my stint with a card processor

MPH80

Equally - there's only 999 combinations for CV2 (or 9999 for an Amex) - so the computational power required to simply 'try' all combinations isn't high.

Having said that - Amex makes life easier by placing all details of the card on the front. So you can get a mobile snapshot of a card on a desk easily or from CCTV and get all the details necessary for an online purchase (assuming AVS isn't being used).

M.

Basilb_2

Hi – my amex was fraudulently used as well this week. It wasused online to buy hundreds of pounds of London underground oyster cards. Amexhave stopped the cards and said they will refund the money pending a fraud investigation. They think it may havebeen cloned or someone had stolen my card taken all the details and thenreturned the card. I phoned transport for London who said that someone has setup 3 accounts in my name. They said they must have known my address and my amexdetails to set up an account. Apart from hacking into my account (i’m prettygood with passwords / internet security) i’m not sure how they would have gotthis info. Any one any idea? I only use the amex for supermarket shopping as ithas good cashback – so not used in on any ‘dodgy’ sites as amex were implying imay have done! I do use for tesco grocery deliverys and is the only place wheremy address and amex details are together. Overall i’m not that impressed of thesecurity of either amex or transport for London.