DDoS Attack On DNS Provider Disrupts Okta, Twitter, Pinterest, Reddit, CNN, Others

[UPDATED 2:40pm ET to reflect another wave of DDoS attacks on Dyn]

A major distributed denial-of-service (DDoS) attack on Internet domain service provider Dyn in the early morning hours on the East Coast today disrupted major websites - including Okta, CNN, Pinterest, Reddit, and Twitter - and provided a grim reminder of the vulnerability of a key element of the Internet's infrastructure.

The Domain Name Service (DNS) basically translates website names into their actual Internet addresses so that when a browser visits a website, for example, the machine is able to find that site.

Dyn said the DDoS attack affected its Managed DNS customers on the East Coast, and service was restored at 9:20 am Eastern Time. The attack began around 7:10 am Eastern Time: "Starting at 11:10 UTC on October 21st-Friday 2016 we began monitoring and mitigating a DDoS attack against our Dyn Managed DNS infrastructure. Some customers may experience increased DNS query latency and delayed zone propagation during this time," Dyn said in a post on its website.

The attacks left websites either inaccessible or with slow-loading pages for some users. Some customers of Okta, the cloud-based multifactor authentication provider, were unable to access servers secured with Okta authentication, including virtual private networks (VPNs). "Our DNS provider is experiencing an issue, preventing lookup of records for some subdomains. Our team is working diligently to fix this," Okta said via Twitter.

Dyn has not provided any details about the nature of the DDoS attack, nor who might be behind it. But speculation ran high, including questions about whether the attacks could be retribution for Dyn's own research about unsavory Internet abuse by some providers, as reported by KrebsOnSecurity.

Some security experts debated whether the attack was a "dry run" by Russian nation-state hackers for the US's election day, where concerns about attacks on news outlets reporting the results of the election could be disrupted via DDoS or other attacks. It wouldn't be unprecedented: self-proclaimed Russian loyalists waged DDoS attacks on NATO and Ukrainian media websites in March of 2014 after NATO's then-secretary general Anders Fogh Rasmussen announced that NATO would not recognize the results of the planned "so-called referendum in Ukraine's Autonomous Republic of Crimea."

KrebsOnSecurity pointed out that the DDoS on Dyn hit after a Dyn researcher presented at the North American Network Operators Group (NANOG) in Dallas on suspicious BGP (Border Gateway Protocol) hijacks and DDoS-for-hire operations. But researcher and blogger Brian Krebs stopped short of attributing today's attack to that presentation. "I have no data to indicate that the attack on Dyn is related to extortion, to Mirai or to any of the companies or individuals [Dyn's Doug] Madory referenced in his talk this week in Dallas," he wrote.

Dyn Managed DNS advanced service monitoring is currently experiencing issues. Customers may notice incorrect probe alerts on their advanced DNS services. Our engineers continue to monitor and investigate the issue. 

[UPDATE: At noon ET today, Dyn was hit with another DDoS attack. As of 2:23pm ET, the company said it was experiencing problems with its Dyn Managed DNS advanced service monitoring: "Customers may notice incorrect probe alerts on their advanced DNS services. Our engineers continue to monitor and investigate the issue."]

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