LinkedIn Outage Caused by DDoS

Monday, June 24, 2013 @ 06:06 PM gHale

The lack of service suffered by LinkedIn last week was the result of an issue with DNS servers as cyber criminals were not directly responsible for the downtime, they indirectly played a part.

Cisco researchers monitored the events and they found a number of organizations with domain names registered with Network Solutions had problems similar to LinkedIn.

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“Their DNS nameservers were replaced with nameservers at The nameservers at were configured to reply to DNS requests for the affected domains with IP addresses in the range,” said Cisco’s Jaeson Schultz.

“Cisco observed a large number of requests directed at these confluence-network IP addresses. Nearly 5000 domains may have been affected based on passive DNS data for those IPs.”

Network Solutions officials said they were the victim of a distributed denial-of-service (DDoS) attack.

“In the process of resolving a Distributed Denial of Service incident on Wednesday night, the websites of a small number of Network Solutions customers were inadvertently affected for up to several hours,” Network Solutions said.

They reassure customers that no data suffered compromise as a result of the incident.

The issues experienced by LinkedIn and others are the result of both malicious activity and misconfiguration.

“Interestingly, several of these domains were setup under different nameservers at For example, the domain was pointed to the DNS nameservers and Yelp had their nameservers changed to and,” Schultz noted.

“Fidelity, meanwhile, was pointed at and However, the fact that so many domains were displaced in such a highly visible way supports Network Solutions’ claim that this was indeed a configuration error.”

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