Two of the most pervasive and dangerous types of software for stealing money from bank accounts have been improved and can now transfer money out automatically, without a hacker's supervision, researchers said.

The latest variants of the widespread SpyEye and Zeus programs have already stolen as much as 13,000 euros ($16,487) at a time from a single account and are in the early stages of deployment, according to investigators at Trend Micro Inc, a Japan-based security company that has many banks as customers.

Trend Micro Vice President Tom Kellerman told Reuters that his company's researchers had seen the new attacks on a dozen financial institutions in Germany, the United Kingdom and Italy. That is troubling because European banks generally have greater technology defenses than those in the United States, and Kellerman said it is "inevitable" that the variants will cross the Atlantic.

The new code has the potential to dramatically escalate the amount being stolen from accounts and a years-old arms race between the banks and criminal groups that are often based in Eastern Europe.

"This has tremendous implications," especially as Americans move toward banking by phone, said Kellerman. "This attack toolkit ushers in a new era of bank heists."

Like other security companies, Trend Micro profits by selling software and services to institutions and consumers worried about online spying and account takeovers.

Though written and controlled by different groups, SpyEye and Zeus share the ability to be installed on computers that visit malicious websites or legitimate pages that have been compromised by hackers. Both programs are sold in the burgeoning underground hacking economy, where they can be customized or improved with additional modules like those just discovered.

The programs already have used a technique called "web injection" to generate new entry fields when victims log on to any number of banks or other sensitive websites. Instead of seeing a bank ask for an account number and password, for example, a victimized user sees requests for both of those and an ATM card number. Everything typed in then gets whisked off to the hacker, who later signs in and transfers money to an accomplice's account.

Those transfers can be time-consuming, and the hacker has to think about how much can be sent out at once without drawing attention. Multiple, smaller transfers are preferable but take more time.

For the past year or more, some variants have also captured one-time passwords sent from the banks by text messages to client cell phones as an added security measure. But in those cases, a hacker had to be online within 30 or 60 seconds in order to use the one-time password.

The new software allows the criminal to siphon money out while he sleeps. It could significantly increase the number of hacked accounts and the speed with which they are drained.

Brett Stone-Gross, a senior security researcher with Dell Inc unit Dell SecureWorks, said thieves "will be able to extract more money" with automation.

But he also said the landscape might not be transformed by the development, because the main limiting factor for crime groups is the number of accomplices, known as money mules, that they can hire to accept transfers from victim accounts. Automation will not lessen the need for mules, Stone-Gross said.

BASED IN EASTERN EUROPE

Trend Micro spoke online with sellers of the automated transfer modules who were based in Russia, Ukraine and Romania, where arrests and prosecutions are rare. Kellerman said the new software costs between $300 and $4,000 on top of the basic thieving tools, with customized jobs costing still more.

So far, the company has seen it run only on top of Microsoft Corp's Windows operating system, which is by far the most common for personal computers.

Banks generally make individuals whole for such losses if they are detected quickly. But recent versions of SpyEye and Zeus can present fake account balances to individual bank customers, so they might not realize their savings are being drained until too late.

Kellerman recommended that banks move more toward "out-of-band" authentication, such as direct phone calls to confirm online transfers.

In the United States, financial regulators last June also called for such checks and urged banks to explore newer technologies to combat Internet fraudsters.