Today's denial of service (DOS) attack on Twitter is the latest in a series of electronic attacks this year on major Internet properties, which have targeted large web hosts and domain registrars, and more recently have expanded to prominent social media sites.
The attacks knocked Twitter offline for most of the morning, with both Netcraft and Pingdom reporting about three hours of downtime. Twitter co-founder Biz Stone confirmed that the outage was caused by a denial of service attack, which affected both the Twitter web site and the services that access Twitter data via API calls, according to the Twitter status page.
UPDATE: Facebook is now confirming that its performance problems this morning were caused by a similar attack. "Earlier this morning, Facebook encountered network issues related to an apparent distributed denial of service attack, that resulted in degraded service for some users,” the company said in a statement. “No user data was at risk and we have restored full access to the site for most users."
UPDATE 2: Sources at Facebook tell CNet's Elinor Mills that today's attacks targeted the profile of a single user on multiple social media sites, including Twitter, Facebook, LiveJournal, Blogger and YouTube. "It was a simultaneous attack across a number of properties targeting him to keep his voice from being heard," said Max Kelly, chief security officer at Facebook.
While Twitter has a history of uptime challenges, other recent attacks have disrupted service at some of the largest hosting providers, including companies who are experienced in defending against these type of attacks. Here's a review of the major attacks seen in 2009:
- Aug. 2-3: Sites in the Gawker Media network, which includes some of the most ppopular blogs, were offline for extended period due to a denial of service attack. (More from the New York Times).
- July 28: Dedicated server provider SoftLayer Technologies and domain registrar Dotster are each hit with a large denial of service attacks targeting their domain name servers. The attack on SoftLayer caused availability problems for TechMeme and TwitPic, while thousands of web sites hosted at Dotster were down.
- April 6-7: Customers of The Planet are hit by web site outages as a result of a DDoS aimed at the huge hosting company. "We will be updating DNS to mitigate attack risks further, but the attack volume was massive," The Planet said on its Twitter stream. "Given the volume of the attack, our network operations team rerouted all name server traffic through our DDoS mitigation capabilities." The Planet hosts more than 48,000 servers.
- April 2-5: Domain registrar Register.com is hit with a DDoS that causes several days of disruptions for its customers. Register.com is the eighth-largest registrar, managing 2.7 million domains.
- March 30-April 1: Cloud computing provider GoGrid is hit by a "large, distributed DDoS attack," which disrupts service to about half of its 1,000 customers. "We’ve been in the hosting business for over 8 years now, and have generally been able to prevent most incidents from impacting customers as heavily as this attack did," GoGrid said on its blog.
- March 31: A DDoS attack knocks UltraDNS offline for several hours. UltraDNS, which is owned by NeuStar, runs high-availability DNS services for online retailers and companies including Oracle and Juniper. Successful attacks on DNS providers are not unprecedented, but these services are designed to be more resilient than standard provider DNS servers.
- Jan. 23-24: An denial of service attack on the DNS servers for large web host and registrar Network Solutions caused downtime or poor performance for hundreds of thousands of web sites.
Denial of service attacks use large networks of computers (often compromised desktop computers) to generate traffic that overwhelms a web site or network. These attacks have become more powerful in recent years as these "botnets" have grown in size.
Obviously, there's no way to know whether any of these attacks are connected. But a worrisome common thread is that these were all large-scale attacks that disrupted service for large providers.