Twitter officials say it was a “cascading bug” and not the handiwork of hacktivists that brought down the microblogging site today in two separate outages.
“This wasn’t due to a hack or our new office or Euro 2012 or GIF avatars, as some have speculated today,” Mazen Rawashdeh, the company’s vice president of engineering, wrote in a blog post. “A ‘cascading bug’ is a bug with an effect that isn’t confined to a particular software element, but rather its effect ‘cascades’ into other elements as well. One of the characteristics of such a bug is that it can have a significant impact on all users, worldwide, which was the case today. As soon as we discovered it, we took corrective actions, which included rolling back to a previous stable version of Twitter.”
The statement was issued after reports began surfacing that the hacker collective UGNazi was behind the outages.
Group members sent e-mails to various news outlets, including Reuters, claiming credit for the service disruption by launching a DDoS attack because of the company’s support for the Cyber Intelligence Sharing and Protection Act.
The hacking group has claimed responsibility in the past for attacks on Google, BP, Comcast and other high-profile companies to protest a number of political and social causes. Most recently, the group was associated with hijacking CloudFlare CEO Matthew Prince’s Gmail account.
Rawashdeh said the first Twitter outage occurred around 9 a.m. Pacific time. The site was back online after about an hour, only to be dropped again 30 minutes later. Full recovery began at 11:08 PDT.
“For the past six months, we’ve enjoyed our highest marks for site reliability and stability ever: at least 99.96% and often 99.99%. In simpler terms, this means that in an average 24-hour period, twitter.com has been stable and available to everyone for roughly 23 hours, 59 minutes and 40-ish seconds. Not today though.”
Indeed among Twitter’s 140 million users were those who reacted with mock outrage, complaining about their inability to complain on Twitter about the interruption in service. Someone created the account @CascadedBug to parody the event with tweets such as “Gnawing on a few cables in Twitter’s mainframe. You’ll never catch me, engineering nerds!”
The account was suspended later in the day.