Twitter has lifted the lid on its recent advice to many users to reset their passwords for the micro-blogging site.
Originally, it was thought that the guidance had come in response to a common or garden phishing attack. In a post on Tuesday, Twitter explained that the attack was actually far more devious and elaborate.
Hackers established Torrent user sites and forums with hidden backdoors. They waited for these forums to grow in popularity before they harvested login details.
These login credentials were then used in attempts to break into accounts on third party sites such as Twitter. The attack relied on the frequent mistake of using the same password and user ID combination for multiple sites.
In other words, victims are using the same password/userID combo on warez forums and Twitter, a mistake that left them open to attack because unidentified hackers had backdoor access to these forums.
Twitter detected the attack after it became suspicious of a "sudden surge in followers" to two previously obscure accounts last week. Followers of these accounts were advised to change their passwords over concerns that hackers involved in the attack had compromised their accounts to, err, gain more followers on Twitter.
It's unclear how many profiles were pwned by the attacks or what other sites might have been involved. All might have been prevented via the use of rudimentary password security precautions.
"The takeaway from this is that people are continuing to use the same email address and password (or a variant) on multiple sites," writes Del Harvey director of Trust and Safety at Twitter. "We strongly suggest that you use different passwords for each service you sign up for," he adds. ®