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By Javier E. David, CNBC

The denial of service attack that crippled servers across the U.S. East Coast on Friday was the result of a "sophisticated, highly distributed" assault that involved millions of internet addresses and a malicious source code, according to Dyn.

The internet traffic company released a blog post in which it gave preliminary findings on the attack, adding that it was still conducting a thorough investigation.

It confirmed that "one source of the traffic for the attacks were devices infected by the Mirai botnet," disruptive software deployed most recently against Krebs on Security and foreign intelligence services, according to Flashpoint.

This photo shows Dyn, a New Hampshire internet service company, in the old mill section of the city, Friday Oct. 21, 2016 in Manchester, N.H.Jim Cole / AP

In addition, "we observed [tens] of millions of discrete IP addresses associated with the Mirai botnet that were part of the attack," Dyn wrote.

The attack comes amid heightened cybersecurity fears and a rising number of internet security breaches. Preliminary indications suggest that countless Internet of Things (IoT) devices that power everyday technology like closed-circuit cameras and smart-home devices were hijacked by the botnet protocol, and used against the servers.

The company plays a critical role in the web's infrastructure, essentially serving as the internet's version of the Yellow Pages. When its architecture was attacked, it took down a host of major sites, including Twitter, Tumblr and

This story first appeared on CNBC.