In what is said to be its largest outage in eight months, Twitter experienced several service interruptions Thursday afternoon, with one outage lasting at least 40 minutes according to various reports. Data from analyst firms such as Sandvine, Apica and Pingdom show sporadic downtime starting at approximately 11AM ET.
Pingdom specifically cites downtime between 11:59AM PT and 1:08PM ET in addition to many briefer outages.
As of writing (5:30PM ET), the service appears to be working properly, though the company hasn't posted a status update since earlier today, at which point engineers were working to resolve the issue: "Users may be experiencing issues accessing Twitter. Our engineers are currently working to resolve the issue. Update: The issue is on-going and engineers are working to resolve it," the company wrote on its status blog.
Hackers of UGNazi quickly took credit for the downtime, with member Hannah Sweet (a.k.a. "Cosmos" and @CosmosTheGod) claiming the group disabled Twitter for 40 minutes worldwide with a distributed denial of service (DDoS) attack – a favorite weapon among hackivists and other mischievous Webgoers. Sweet said UGNazi is targeting Twitter because it supports the Cyber Intelligence Sharing and Protection Act (CISPA).
Despite Sweet's claims, Twitter says the outage is due to a cascaded bug in one of its infrastructure components, promising more details soon.