Jan. 6, 2012 at 6:11 AM ET
The best way to protect yourself from an online financial scam is to diligently check your bank accounts. At least, until now.
Israeli-based Security firm Trusteer has found an elaborate new computer virus that not only helps fraudsters steal money from bank accounts -- it also covers its tracks.
Think of a crime plot involving a spy who plans to break into a high-security building and beginsby swapping out security camera video so guards don't notice anything is amiss. Known as a surveillance camera hack, the technique has been used in dozens of movies.
A new version of the widely prevalent SpyEye Trojan horse works much the same way, only it swaps out banking Web pages rather than video, preventing account holders from noticing that their money is gone.
The Trojan horse employs a powerful two-step process to commit the electronic crime. First, the virus lies in wait until a customer with an infected computer visits an online banking site, steals their login credentials and tricks the victim into divulging additional personal information such as debit card information. Then, after the stolen card number is used for a fraudulent purchase, the virus intercepts any further visits to the victim's banking site and scrubs transaction records clean of any fraud. That prevents -- or at least delays -- consumers from discovering fraud and reporting it to the bank, buying the fraudster critical extra time to complete the crime.
Trusteer calls it a "post transaction" attack, because much of the virus' effectiveness is attributable to its ability to control what victims see after fraudulent transactions occur. Amit Klein, chief technology officer for Trusteer, said he believes criminals have used the technique for a few months, and it has infected real consumers.
"I predict that the use of post transaction attack technology will significantly increase as it enables criminals to maximize the amount of fraud they can commit using their initial investment in malware toolkits and infection mechanisms," Klein said.
The new SpyEye came to Trusteer's attention when a large retail bank in the United States spotted it and shared with the firm, he said.
'A very scary tactic'
The virus' evidence-covering techniques are elaborate. First, it keeps track of all fraud committed by the criminal, and makes sure to remove those line items from online transaction lists. It also edits balance amounts to prevent consumers from getting suspicious.
"This is a very scary tactic," said Avivah Litan, a financial fraud analyst at consulting firm Gartner. "Everybody thinks all they have to do is check their transactions and their balances. That's not true anymore."
The new virus technique ups the ante in the cat-and-mouse game between security companies and the computer criminals who try to steal consumers' money. Consumer reports of fraud are still a very important part of fraud-fighting techniques, Litan said.
"Most banks 'let the first transaction through,' because if they stopped everything that was potentially fraud, consumers would get annoyed," she said. In some cases, fraud-checking tools kick in only after initial reports, so this version of SpyEye could buy criminals important time as they try to turn stolen data into cash.
"Usually they only need one day more to get the money, to push the fraud through," she said. "They always want to keep the security guys running after them."
Such cover-your-tracks techniques have been used before by virus writers, Klein said. In a simpler version, criminals who raided online bank accounts and wired money out of them would try to hide the transaction from victims using the same Web page interception trick. But this new flavor has more potential for success, because it involves stolen debit card numbers used at third-party merchants, creating complex transactions involving multiple banks and multiple security systems.
Victim account holders who check their balance at an ATM -- or even at a second uninfected computer -- would be able to spot the fraudulent transactions. The virus doesn’t impact bank systems, merely the characters that are displayed within the infected system's Web browser. That means paper statements would reveal the fraud, too.
Of course, consumers who rely on paper statements could be a full 30 days behind when it comes to spotting fraudulent transactions.
While Klein is worried about the "post transaction" attack, he said consumers who have vulnerable Web browsers are bound to be victims of one fraudster or another.
"My take is that if your computer is infected with financial malware, it's game over anyway," he said. "My takeaway is you need to prevent getting infected with financial malware in the first place."
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