An analysis of nearly 40,000 passwords stolen from Sony Pictures by the hyperactive LulzSec crew shows that people persist in re-using passwords, a dangerous practice in light of frequent Web site break-ins, a researcher has said.
Using publicly-available copies of the password files put online by LulzSec, Australian software architect Troy Hunt crunched the numbers to come up with some disturbing trends.
"What surprised me was the extent of [password] re-use," Hunt said in an interview today. "People use and re-use the same password. That's one of the most dangerous of all the bad password practices."
On June 2, LulzSec announced it had hacked several Sony Pictures Web sites and walked off with personal information on more than 1 million users, including email addresses, usernames and passwords for a pair of Sony-sponsored promotional campaigns: "Seinfeld: We're Going to Del Boca Vista! Sweepstakes" and "Summer of Restless Beauty."
LulzSec also claimed it had hacked several other Sony databases.
Hunt compared the files that LulzSec posted online for the two promotions -- which together contained more than 37,000 accounts -- and discovered that 92% of the 2,000 accounts with the same email address also used the same password.
"That's a pretty damning indictment of the whole 'unique password' mantra," said Hunt in a blog post he wrote last week.
Hunt also compared the Sony Pictures passwords to those published last year by "Gnosis," a hacking group that claimed credit for an attack against Gawker , which publishes several popular technology sites, including Gizmodo and Lifehacker.
Gnosis posted almost 190,000 Gawker account email addresses and passwords last December.
Hunt mapped the Sony Pictures and Gawker files to see if the high password re-use between the two Sony databases was an anomaly, perhaps caused by the fact that people used the same password throughout the Sony ecosystem.
Of the 88 accounts at both sites that relied on the same email address, 67% used the same password, said Hunt.
"Two-thirds of the passwords used for accounts at both Sony and Gawker were re-used, even though these were two very autonomous sites. So how many Gmail or eBay or Facebook accounts are we holding the keys to here?" asked Hunt, referring to the LulzSec-stolen Sony Pictures data.
Security experts have repeatedly warned users about re-using passwords on multiple sites because one compromised account can have a domino effect.
"If you use different passwords [for each site or account], then if one is stolen, the damage is constrained to that one location," said Hunt. "But if you apply the same password to a lot of sites, it opens Pandora's box each time a database is hacked."
Hunt recommended users try a password manager that creates unique passwords for each site or account, remembers those passwords, and then slaps them into place either automatically or at command.
"If the mousetrap is single-factor passwords, we need a better mousetrap," said Hunt, who argued that two-factor authentication, while suitable for businesses, wasn't going to fly for consumers. "So you need long and random and unique passwords. But you can't do that without a password manager," he said.
LastPass, however, warned customers last month to change their master passwords after reporting what it called a "traffic anomaly" on one of its servers.
Hunt also did additional analysis on the Sony Pictures passwords leaked by LulzSec, and confirmed what earlier research -- including some done last year by Michigan-based Duo Security on the Gawker passwords .
Like Duo, Hunt found that the vast majority of passwords were too short, built on too-few character types, and were not unique enough to stand up to simple dictionary-based attacks.
"The only secure password is one you can't remember," said Hunt.