Canonical claims to have found the root cause of the security breach that reportedly led to millions of Ubuntu Forum users having their email and passwords compromised.
The Ubuntu developer took the web forum down, which is used by people who want to discuss the workings of the Linux-based operating system, on Saturday.
It's really not hard, when both sides of an arrangement live up to their security obligations to make things very difficult for the bad guys out there.
This followed a defacement of the forum by hackers, who gained access to every member's email address, hashed password and username.
At the time of writing, the site was still down, but a holding page set up to alert forum users about the breach claims the firm is getting closer to revealing how the hackers accessed its systems.
"We believe the root cause of the breach has been identified [and] we are currently reinstalling the forums software from scratch," the holding page states.
"No data (posts, private messages, etc.) will be lost as part of this process."
Canonical CEO Jane Silber advised users in a blog post dated 21 July to assume their passwords have been accessed and to change them.
She also confirmed the company has started notifying affected users by email, and at this time has no reason to believe the hackers accessed other Ubuntu or Canonical sites or services.
"We are continuing to investigate exactly how the attackers were able to gain access and are working with the software providers to address that issue," she said.
"Once the investigation is concluded, we will provide as much detail as we safely can."
According to reports, around 1.8 million users are thought to have been affected by the breach.
Graham Cluley, former Sophos senior technology consultant and independent IT security expert, said the hackers could have accessed the site in several ways.
"It's possible the administrators of Ubuntu Forums weren't doing a great job at keeping their forum and server software up-to-date and this could have allowed the hackers to exploit a vulnerability," he offered in a post on his website.
He also claimed the breach could leave users at risk of account hacking and spam emails.
However, Conrad Constantine, Ubuntu Forum's member and research engineer and at security vendor AlienVault, said he was happy with Canonical's handling of the breach.
"Ubuntu did its part (making sure the impact of the password database being stolen is minimised, via salted, hashed entries), [and] I've done my part (making sure that I don't use the same credentials for a lower-security site like the Ubuntu Forums, on a higher security site, like my online banking)," he said.
"It's really not hard, when both sides of an arrangement live up to their security obligations to make things very difficult for the bad guys out there," he added.
*This article was originally posted on 22 July, and updated today to reflect new information about the Ubuntu hack.
