Denial-of-service attack cripples Twitter

Twitter was inaccessible for several hours on Thursday morning, followed by a period of slowness and sporadic time-outs (and more outright downtime). The company is blaming an “ongoing” denial-of-service attack but has not said anything further.

Judging by the timeline of my TweetDeck client, it looks like the problems started right around 6 a.m. PDT.

“We are determining the cause and will provide an update shortly,” Twitter’s staff posted at 6:43 a.m. PDT on the service’s status blog.

Then, around 7:49 a.m. PT, the company posted, “We are defending against a denial-of-service attack and will update status again shortly.”

Around 8:15 a.m., the status blog post was updated with “The site is back up, but we are continuing to defend against and recover from this attack.” (I still was unable to access Twitter.)

Perfomance monitoring firm AlertSite says that Twitter’s home page went down at 6:05 a.m. PT and was showing 40 percent availability at 8:04 a.m. PT, but that timeouts were continuing from most of its monitoring locations at 8:30 a.m.

Way back when, Twitter outages were so commonplace that it was worth reporting when it didn’t crash–as when it stayed afloat during the entire South by Southwest Interactive Festival in 2008. Now, a few million dollars of venture capital later, the service is far more stable.

Twitter wants to establish itself as a communications standard rather than just a social-media brand. It’s been a crucial platform for information exchange in the face of global events where more traditional means of broadcasting have been inaccessible or blocked.

Some features of Facebook were also experiencing uptime issues on Thursday–one reader speculated that log-in servers may have been down–which raises the issue of whether a hosting company problem is to blame. Alternately, a denial-of-service attack could have been targeting both high-profile companies.

Facebook responded later in the morning on Thursday with a statement. “Earlier this morning, we encountered issues within our network that resulted in a short period of degraded site experience for some visitors,” the statement read. “No user data was at risk and the matter is now resolved for the majority of users. We’re monitoring the situation to ensure that users continue to have the fast and reliable experience they’ve come to expect from Facebook.”

Click here for the CNET News story.