The threat is greatest for those who don't change their default passwords after using them to bring the router online. According to an informal study by Indiana University, up to 50% of home broadband users fail to reset the password after installing their router.
"What worries me if that it's so simple for people to fall for this kind of attack," said Zully Ramzan, senior principal researcher for Symantec Security Response. "Most people connect to the Internet through broadband today, but they don't adequately protect their routers."
Such fraudulent sites are an almost exact replica of the actual site so the user won't likely notice the difference. Once the user is directed to the pharmer's "bank" site and enters their user name and password, the attacker can steal the information and access the victim's account to transfer funds, create new accounts and write checks.
While the threat affects mostly home users, Ramzan said enterprise environments are also at risk.
"A lot of people take their laptops home and work off their home router," he said. "One of the ways people break into networks is by stealing credentials from a compromised laptop."
His advice to users is to reset their router passwords at least once -- the day it is hooked up to the home or office computer system. If the password is changed every few months, that's even better.
Professor Markus Jakobsson of the Indiana University School of Infomatics the new attack technique shows how important the human factor is in security
"While drive-by pharming arises due to inadequate protective measures, there is also another human component: If an attacker can trick you into visiting his page, he can probe your machine," he said in a statement. "Deceit is not new to humankind, but it is fairly recently that security researchers started taking it seriously."