By BRAD STONE
February 5, 2007
Internet security experts have long known that simple passwords do not
fully defend online bank accounts from determined fraud artists. Now a
study suggests that a popular secondary security measure provides little
The study, produced jointly by researchers at Harvard and the
Massachusetts Institute of Technology, looked at a technology called
site-authentication images. In the system, currently used by financial
institutions like Bank of America, ING Direct and Vanguard, online
banking customers are asked to select an image, like a dog or chess
piece, that they will see every time they log in to their account.
The idea is that if customers do not see their image, they could be at a
fraudulent Web site, dummied up to look like their banks, and should not
enter their passwords.
The Harvard and M.I.T. researchers tested that hypothesis. In October,
they brought 67 Bank of America customers in the Boston area into a
controlled environment and asked them to conduct routine online banking
activities, like looking up account balances. But the researchers had
secretly withdrawn the images.
Of 60 participants who got that far into the study and whose results
could be verified, 58 entered passwords anyway. Only two chose not to
log on, citing security concerns.
The premise is that site-authentication images increase security because
customers will not enter their passwords if they do not see the correct
image, said Stuart Schechter, a computer scientist at the M.I.T. Lincoln
Laboratory. From the study we learned that the premise is right less
than 10 percent of the time.
He added: If a bank were to ask me if they should deploy it, I would say
no, wait for something better, he said.
The system has some high-power supporters in the financial services
world, many trying to comply with new online banking regulations. In
2005, the Federal Financial Institutions Examination Council, an
interagency body of federal banking regulators, determined that
passwords alone did not effectively thwart intruders like identity
It issued new guidelines, asking financial Web sites to find better ways
for banks and customers to identify each other online. January 2007 was
set as the compliance date, though the council has yet to begin
enforcing the mandate.
Banks immediately knew what they did not want to do: ask customers to
download new security software, or carry around hardware devices that
feed them PIN codes they can use to authenticate their identities. Both
solutions would add an extra layer of security but, the banks believed,
detract from the convenience of online banking.
The image system, introduced in 2004 by a Silicon Valley firm called
PassMark Security, offered banks a pain-free addition to their security
arsenals. Bank of America was among the first to adopt it, in June 2005,
under the brand name SiteKey, asking its 21 million Web site users to
select an image from thousands of possible choices and to choose a
unique phrase they would see every time they logged in.
SiteKey gives our customers a fairly easy way of authenticating the Bank
of America Web site, said Sanjay Gupta, an e-commerce executive at the
bank. It was very well received.
The Harvard and M.I.T. researchers, however, found that most online
banking customers did not notice when the SiteKey images were absent.
When respondents logged in during the study, they saw a site maintenance
message on the screen where their image and phrases should have been
pictured. The error message also had a conspicuous spelling mistake,
further suggesting something fishy,.
Mr. Gupta of Bank of America said he was not troubled by the results of
the survey, and stressed that SiteKey had made the banks Web site more
secure. He also said that the system was only a single part of a larger
security blanket. Its not like were betting the bank on SiteKey, he
Most financial institutions, like Bank of America, have other ways to
tell if a customer is legitimate. The banks often drop a small software
program, called a cookie, onto a users PC to associate the computer with
the customer. If the customer logs in from another machine, he may be
asked personal questions, like his mothers maiden name.
Rachna Dhamija, the Harvard researcher who conducted the study, points
out that swindlers can use their dummy Web sites to ask customers those
personal questions. She said that the study demonstrated that
site-authentication images are fundamentally flawed and, worse, might
actually detract from security by giving users a false sense of
RSA Security, the company that bought PassMark last year, has a lot of
great data on how SiteKey instills trust and confidence and good
feelings in their customers, Ms. Dhamija said. Ultimately that might be
why they adopted it. Sometimes the appearance of security is more
important than security itself.
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