The operations center for a credit card processing firm whose security was breached by a hacker, exposing 40 million accounts to possible fraud, has put new security software in place.

Marc Maiffret, a computer security specialist and co-founder of eEye Digital Security of Aliso Viejo, Calif., said his firm installed the security upgrade for Atlanta-based CardSystems Solutions' operations center here on June 10.

On Friday, MasterCard International Inc. disclosed that 40 million credit card accounts belonging to it and other companies were exposed to possible fraud by a security breach at CardSystems Solutions' operations center here, the latest in a string of recent breaches at financial institutions.

Maiffret told the Arizona Daily Star that the upgrade his firm sold CardSystems Solutions was in place three days later. CardSystems may have initiated other measures as well in response to the breach, he added.

Calls to Maiffret and spokesmen for eEye Digital and CardSystems Solutions were not returned immediately Thursday.

CardSystems Solutions is among a large number of companies processing financial transactions for credit card issuers that largely use custom-made software applications not initially designed with security components as their foremost need, Maiffret said.

In addition, such third-party companies frequently must contend with budget constraints causing them to be stingy on computer security, Maiffret said.

Those settings make for favorable conditions for a skilled hacker to manipulate his way through a computer program seeking vulnerabilities, he added.

"There is really no standard for how all this financial information gets pushed around, and all these companies push it around a little differently," Maiffret told the Star.

"That means you also have all these little quirks and opportunities for a hacker who has the time to find weaknesses."

Associated Press