NEW YORK (CNNMoney.com) -- Popular news and gossip blog network Gawker fell victim this weekend to hackers: Over 1 million usernames and passwords were exposed by a group of hackers who posted a 500 MB file of the private data on a file-sharing site.
The breach exposed users' passwords and e-mails, as well as Gawker's source code and conversations between staff members.
Speculation that the site's security had been breached began after a series of suspicious tweets on Saturday from affiliated site Gizmodo, according to Mediaite.
Gawker's management acknowledged the breach late Sunday, posting on Lifehacker.com: "This weekend we discovered that Gawker Media's servers were compromised, resulting in a security breach at Lifehacker, Gizmodo, Gawker, Jezebel, io9, Jalopnik, Kotaku, Deadspin, and Fleshbot."
The site advised its registered commenters to "assume that your username and password were included among the leaked data," and to change their passwords. As Jessica Coen, editor-in-chief of Gawker sister site Jezebel, phrased it on Twitter: "If you've registered to comment on Jezebel, pls change your password before your computer bursts into flames."
To combat future attacks, the site plans to hire an independent security firm to improve the security. Gawker founder, Nick Denton, was unavailable for further comment.
"We're busy communicating with our commenters right now," he told CNNMoney. "That has to take priority."
A group called "Gnosis" contacted various media outlets claiming credit for the attack. In the letter posted on Mediaite, a user who claimed to represent Gnosis wrote: "We went after Gawker because of their outright arrogance. It took us a few hours to find a way to dump all their source code and a bit longer to find a way into their database."
Gawker has previously spoken out against groups like 4chan, a site whose members often band together to take down websites using denial-of-service attacks.
According to Gnosis' letter, the group found the site's security easy to breach. "Their site is filled with numerous exploitable code and their database is publicly accessible," they wrote.
While Gawker is up and running again, the breach has had clear repercussions. Twitter users who had the same password for that site as for their Gawker accounts are reporting intrusions, with a barrage of messages advertising Acai Berry diet links polluting their tweet feeds.
Del Harvey, Twitter's director of trust and safety, advised users to change their Twitter passwords.
"Got a Gawker acct that shares a PW w/your Twitter acct? Change your Twitter PR. A current attack appears to be due to the Gawker compromise," Harvey tweeted.
"Security is very much like 'The Club' on your automobile ... if someone is motivated, persistent, and resourceful, they can ultimately find a way to steal your car," he said. "Through a combination of skill, knowledge sharing, and trial and error, they find a hole that they exploit. This is not surprising or new, it's just currently now much more in the public eye."
Denton later addressed logistical concerns and fielded questions from unhappy users on the comments section of the Gawker site.
One user suggested Denton's dismissive attitude about commenters could have enabled the attack. "You really need to think deeply about how you missed spotting this iceberg," he wrote.
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