As reported previously by Infosecurity, the Anti-Phishing Working Group reported back in May that the Avalanche Group were responsible for two third of all detected phishing attacks in Q3 and Q4 of 2009.
In its analysis of the trend, meanwhile, Imperva says that the attack vectors used by the Avalanche botnet gang – who have taken two years to migrate to the new fraud architecture – indicate that criminal hackers are now using lateral thinking to develop their fraudulent modus operandi.
Amichai Shulman, Imperva's chief technology officer, said that the gang is using advanced programming techniques.
"The problem is that the banks, not the users, are realising that the client browser is actually under the control of the hacker. So although a user is in fact authenticated to the bank, all transactions are actually being performed from that moment on by the Trojan", he explained.
Imperva's research teams, he went on to say, have concluded that using a man-in-the-browser attack, similarl to those uncovered in September, enables the electronic criminals to stage automated withdrawals.
"The problem of detecting this type of fraud is made all the more difficult as the banks are not aware that the initiator of the transaction is not the actual owner of the account but basically, an automated process", he said.
"This is why some financial institutions, such as Sainsbury's Bank now require users to confirm by mobile phone text message when a new account payee is set up," he added.
"Until the banks are able to prevent against this type of complex malware-driven fraud, the cybercriminal gangs will continue to evolve their already sophisticated strategies to beat the banks - and their customers."