Criminals in Germany are exploiting a loophole in the banking system to get hold of customers' account details. They transfer one cent to random account numbers - if the transfer goes through, they know they've hit the mother lode.

Paying bills in Germany can be a remarkably simple affair. In a country where checks are shunned, a simple bank transfer - made either at the bank or from in front of the computer screen - is the way to go.

But efforts to speed up the system have laid it open to abuse, as a new scam shows.

According to German authorities, criminals attempt to transfer the sum of 1 euro cent to several accounts at a particular bank, using account numbers they have generated at random. If the payment gets rejected by the bank, then the account number does not exist - but if the transfer goes through successfully, then the crooks know they have stumbled upon a genuine account number. It's a similar approach to that sometimes used by the senders of e-mail spam, who may compile mailing lists by generating random email addresses and checking to see which of those accounts accept the messages.

The beauty of the 1-cent trick is that, even if the account holder notices the transfer, it is unlikely to arouse their suspicions. Apart from anything else, it is extra money in their account - even if only 1 cent. The fraudsters don't even need to know the name of the account holder, as the account number on the transfer slip is read by a machine, which doesn't check whether the name and account number match.