INCREASING RISKS: A new study finds that online banking customers are more vulnerable to fraud when their banks’ Web sites have design flaws that teach bad surfing habits.

WIDESPREAD DANGERS: University of Michigan researchers found such design flaws in 76 percent of the 214 U.S. financial institution Web sites they studied. Researchers aren’t detailing which banks had problems.

THE FINDINGS: Researchers found that many banks silently redirect users to third-party sites, plop “secure login” boxes on insecure Web pages, and improperly use Social Security numbers or e-mail addresses _ which an outsider can figure out _ as default user names.