Denial of Service Attack Hits Websites, Knocking Out Access--Update

By Drew FitzGerald 

Several websites including Twitter and Tumblr were unreachable during an extended period for many internet users Friday following an online attack.

Web technology provider Dyn said its domain name system, or DNS, service was subject to a massive distributed denial of service attack.

Denial of service attacks can knock websites offline by flooding them with junk data, blocking the way for legitimate users. Dyn's DNS services are a key part of the digital supply chain that allow web addresses -- Twitter.com, for instance -- to take users to the infrastructure that hosts them.

"We began monitoring and mitigating a DDoS attack against our Dyn Managed DNS infrastructure" beginning at 7:10 a.m. Eastern time on Friday, the Web service said on its status website.

Dyn said its services were back up by around 9:20 a.m. ET. The company didn't disclose the source of the attack.

Security experts say denial of service attacks have grown more powerful over the past year. A sustained assault on the website of security researcher Brian Krebs last month broke records partly because the network that launched it used hundreds of thousands of connected cameras, digital video recorders and other "smart" devices, according to website defender Akamai Technologies Inc.

Amazon.com Inc. also said it had found the root cause of DNS problems affecting its East Coast cloud customers and resolved the issue, though it didn't disclose the cause. Amazon had said it was looking into an elevated number of errors related to accessing its cloud services in a main East Coast server hub due to DNS issues. Amazon Web Services runs a broad array of websites.

Amazon said the problems occurred between 7:31 a.m. and 9:10 a.m. Eastern time.

Cloud services provider Heroku Inc. also said it was seeing "widespread" DNS issues related to a denial of service attacks against one of its DNS providers.

--Austen Hufford contributed to this article

Write to Drew FitzGerald at [e-mail]

(END) Dow Jones Newswires

October 21, 2016 10:17 ET (14:17 GMT)

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