Security Experts:

Mirai Botnets Used for DDoS Attacks on Dyn

Experts determined that the distributed denial-of-service (DDoS) attacks launched last week against Dyn’s DNS infrastructure were powered by Internet of Things (IoT) devices infected with the malware known as Mirai.

The first attack started on Friday at 7 am ET and it took the DNS provider roughly two hours to mitigate it. During this time, users directed to the company’s DNS servers on the east coast of the U.S. were unable to access several major websites, including Twitter, Reddit, GitHub, Etsy, Netflix, PagerDuty, Airbnb, Spotify, Intercom and Heroku.

A few hours later, a second, more global attack led to some users having difficulties in accessing the websites of Dyn customers. This second attack was mitigated within an hour. A third attack attempt was also detected, but it was mitigated before impacting users.

Dyn Chief Strategy Officer Kyle York pointed out in a blog post that the company “did not experience a system-wide outage at any time.”

Akamai and Flashpoint have confirmed that the attacks leveraged Mirai botnets and Dyn said it had observed tens of millions of IPs involved in the incident.

Mirai botnets, which are known to have ensnared hundreds of thousands of IoT devices, have been used in recent weeks to launch massive DDoS attacks against the website of journalist Brian Krebs and hosting provider OVH.

However, Flashpoint told SecurityWeek that different Mirai botnets have been used in the attacks aimed at Dyn’s DNS infrastructure. The security firm said it was unclear if the attacks aimed at Dyn, Krebs and OVH are in any way connected.

“Dyn is collaborating with the law enforcement community, other service providers, and members of the internet community who have helped and offered to help,” said York.

WikiLeaks suggested on Twitter that the attacks have been launched by Julian Assange’s supporters after the Ecuadorian government decided to cut off his Internet access following the latest email leaks.

The source code of the Mirai malware was leaked in early October and an increasing number of threat groups have been using it to create DDoS botnets since. After analyzing some of the command and control (C&C) servers, Level3 Communications reported last week that it had spotted nearly half a million infected IoT devices that had been part of multiple Mirai botnets.

Related: Serious Flaws Expose AVTECH Devices to IoT Botnets

Related: Over 500,000 IoT Devices Vulnerable to Mirai Botnet

Related: MITRE Offers $50,000 for Rogue IoT Device Detection

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.