Though changing passwords often might seem like a good security practice, in reality, that isn’t the case, says Carnegie Mellon University professor Lorrie Cranor. Earlier this year, when the Federal Trade Commission tweeted that people should “encourage” their loved ones to “change passwords often,” Cranor wasted no time challenging it. From ArsTechnica’s story: The reasoning behind the advice [of changing password often] is that an organization’s network may have attackers inside who have yet to be discovered. Frequent password changes lock them out. But to a university professor who focuses on security, Cranor found the advice problematic for a couple of reasons. For one, a growing body of research suggests that frequent password changes make security worse. As if repeating advice that’s based more on superstition than hard data wasn’t bad enough, the tweet was even more annoying because all six of the government passwords she used had to be changed every 60 days. “I saw this tweet and I said, ‘Why is it that the FTC is going around telling everyone to change their passwords?'” she said during a keynote speech at the BSides security conference in Las Vegas. “I went to the social media people and asked them that and they said, ‘Well, it must be good advice because at the FTC we change our passwords every 60 days.” Cranor eventually approached the chief information officer and the chief information security officer for the FTC and told them what a growing number of security experts have come to believe. Frequent password changes do little to improve security and very possibly make security worse by encouraging the use of passwords that are more susceptible to cracking. The CIO asked for research that supported this contrarian view, and Cranor was happy to provide it. The most on-point data comes from a study published in 2010 by researchers from the University of North Carolina at Chapel Hill.
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