The huge attack on global internet access, which blocked some of the world’s most popular websites, is believed to have been unleashed by hackers using common devices like webcams and digital recorders.

Among the sites targeted on Friday were Twitter, Paypal and Spotify. All were customers of Dyn, an infrastructure company in New Hampshire in the US that acts as a switchboard for internet traffic.

Outages were intermittent and varied by geography, but reportedly began in the eastern US before spreading to other parts of the country and Europe.



Users complained they could not reach dozens of internet destinations, including Mashable, CNN, the New York Times, the Wall Street Journal, Yelp and some businesses hosted by Amazon.

Hackers used hundreds of thousands of internet-connected devices that had previously been infected with a malicious code – known as a “botnet” or, jokingly, a “zombie army” – to force an especially potent distributed denial of service (DDoS) attack.

The aim of a DDoS attack is to overwhelm an online service with traffic from multiple sources, rendering it unavailable. Dyn said attacks were coming from millions of internet addresses, making it one of the largest attacks ever seen.

Dyn said it had resolved one attack, which disrupted operations for about two hours, but disclosed a second a few hours later that was causing further disruptions. By the evening it was fighting a third.

At least some of the malicious traffic was coming from connected devices, including webcams and digital video recorders. 



Security researchers working with Dyn to investigate the attack have linked it to a network of web-enabled CCTV cameras made by a single Chinese company, XiongMai Technologies.

Allison Nixon, director of research at the security firm Flashpoint, said its web-enabled CCTV cameras and digital video recorders were forcibly networked together using the sophisticated malware program Mirai to direct the crushing number of connection requests to Dyn’s customers.

“It’s remarkable that virtually an entire company’s product line has just been turned into a botnet that is now attacking the United States,” she told security researcher Brian Krebs.

The Guardian has contacted XiongMai for comment.

The same Mirai malware was used in September to launch what was then described as the biggest DDoS attack ever on Krebs’ website, Krebs on Security. His reporting on cybercrime has made him a target in the past.



Hackers released the source code for Mirai earlier this month, inspiring a significant number of copycats.

Experts had warned of increasingly sophisticated botnets – in essence, a weaponised combination of malware and as many as 100,000 hijacked individual devices – just days before Friday’s attack.



Researchers at Level 3 Communications, a global communications company focused on managed security, warned earlier this week that “the threat from these botnets is growing” as more and more devices were connected to the web.

The US Department of Homeland Security had issued a warning last week.

Mirai was the most sophisticated botnet malware Level 3 had seen yet, able to rotate the IP addresses (likely to avoid detection) about three times as often as had been observed with other botnets.

More worryingly still, it was “becoming still more sophisticated”.

Mirai targeted household and everyday devices – such as DVRs, cameras and even kettles – that were connected to the internet, a concept of connectivity commonly referred to as “the internet of things” (IoT). Many were devised without particular mind to security.

Level 3 researchers said the majority – as many as 80% – of botnets were networked DVRs, with the rest routers and other miscellaneous devices such as IP cameras and Linux servers.

“The devices are often operated with the default passwords, which are simple for bot herders to guess.”

Michael Mimoso, of cybersecurity research group Kaspersky Lab, estimated on Wednesday that the number of compromised devices had reached 493,000, with most in the US. “But Brazil and Colombia are also high on the list”.



Dyn categorized the attack as “resolved” shortly after 6pm New York time, but it is still not known who deployed the botnet, and why.

“The complexity of the attacks is what’s making it very challenging for us,” the company’s chief strategy officer, Kyle York, told Reuters. Homeland Security and the Federal Bureau of Investigation said they were investigating.

A tweet from WikiLeaks at 5pm Friday New York time implied that its supporters were behind the attack.

“Mr. Assange is still alive and WikiLeaks is still publishing. We ask supporters to stop taking down the US internet. You proved your point.”

Security researcher Bruce Schneier caused waves when he wrote in September that someone, probably a country, was “learning how to take down the internet”.

He wrote that “a large nation state” (“China or Russia would be my first guesses”) had been testing increasing levels of DDoS attacks against unnamed core internet infrastructure providers in what seemed like a test of capability. 



Nixon told Reuters there was no reason to think a national government was behind Friday’s assaults, but attacks carried out on a for-hire basis were famously difficult to attribute. </s> Cybersecurity analysts believe the distributed-denial-of-service attack gainst internet performance company Dyn was carried out using an "Internet of Things" made up of various internet-connected home devices including CCTV video cameras and digital video recorders. Security firm Flashpoint confirmed a form of malware known as Mirai was used to hack products made by Chinese company XiongMai Technologies. The devices feature factory-default usernames and passwords that can not be changed, making them vulnerable to being hacked and used to hurl junk traffic in order to shut down online services. Photo by Twin Design/Shutterstock/UPI

MANCHESTER, N.H., Oct. 22 (UPI) -- Hackers used "smart" home devices connected to the internet as weapons in the cyberattack against internet performance company Dyn, security experts said.

Security analysts believe the Friday distributed-denial-of-service attack, which shutdown popular websites such as Twitter, Spotify, Netflix, Reddit and Amazon was carried out using CCTV video cameras, digital video recorders and other similar devices.

Security firm Flashpoint confirmed the attack used "botnets" infected with a form of malware known as "Mirai" to access an "Internet of Things" made up of various internet-connected home devices, according to the BBC.

"Mirai scours the Web for IoT devices protected by little more than factory-default usernames and passwords, and then enlists the devices in attacks that hurl junk traffic at an online target until it can no longer accommodate legitimate visitors or users," cybersecurity expert Brian Krebs wrote on his blog.

Allison Nixon, director of research at Flashpoint, told Krebs the majority of the devices involved in the attack on Dyn used digital video recorders and IP cameras made by Chinese company XiongMai Technologies.

"It's remarkable that virtually an entire company's product line has just been turned into a botnet that is now attacking the United States," Nixon said.

Krebs, whose website was targeted by a similar attack in September, said the XiongMai devices are "essentially unfixable" and will remain a danger to others unless they are totally removed from the internet.

"The issue with these particular devices is that a user cannot feasibly change this password," Zach Wikholm of Flashpoint said. "The password is hardcoded into the firmware, and the tools necessary to disable it are not present. Even worse, the web interface is not aware that these credentials even exist." </s> CLOSE Jefferson Graham offers 4 tips on how to protect your home network from a hack on #TalkingTech.

This file photo taken on September 11, 2013 shows the logo of social networking website 'Twitter' displayed on a computer screen in London. Twitter was one of the website impacted by Friday's attacks. (Photo: LEON NEAL, AFP/Getty Images)

SAN FRANCISCO — Technology experts warned for years that the millions of Internet-connected "smart" devices we use every day are weak, easily hijacked and could be turned against us.

The massive siege on Dyn, a New Hampshire-based company that monitors and routes Internet traffic, shows those ominous predictions are now a reality.

An unknown attacker intermittently knocked many popular websites offline for hours Friday, from Amazon to Twitter and Netflix to Etsy. How the breach occurred is a cautionary tale of the how the rush to make humdrum devices “smart” while sometimes leaving out crucial security can have major consequences.

Dyn, a provider of Internet management for multiple companies, was hit with a large-scale distributed denial of service attack (DDoS), in which its servers were flooded with millions of fake requests for information, so many that they could no longer respond to real ones and crashed under the weight.

Who orchestrated the attack is still unknown. But how they did it — by enslaving ordinary household electronic devices such as DVRs, routers and digital closed-circuit cameras —is established.

The attackers created a digital army of co-opted robot networks, a "botnet," that spewed millions of nonsense messages at Dyn's servers. Like a firehose, they could direct it at will, knocking out the servers, turning down the flow and then hitting it full blast once again.

The specific weapon? An easy-to-use botnet-creating software called Mirai that requires little technical expertise. An unknown person released it to the hacker underground earlier this month, and security experts immediately warned it might come into more general use.

Mirai insinuates itself into household devices without the owner's knowledge, using them as platforms to send the sever-clogging messages even as the device continues to do its day job for its true owner.

The software uses malware from phishing emails to first infect a computer or home network, then spreads to everything on it, taking over DVRs, cable set-top boxes, routers and even Internet-connected cameras used by stores and businesses for surveillance.

That breadth of "attack surface," as security experts call it, is one of the things that makes Mirai so difficult to fight, said Kyle York, Dyn’s chief strategy officer.

“The complexity of this attack is because it’s so distributed. It’s coming from tens of millions of source IP addresses that are globally distributed around the world. What they’re doing is moving around the world with each attack," he said.

A woman looks at the FBI internet site page dedicated to the DSN Malware on July 9, 2012 in Paris. (Photo: MICHEL RUBINEL, AFP/Getty Images)

Internet of (dangerous) Things

As long as companies have been gleefully making and selling Internet-connected devices (the so-called Internet of Things or IoT), computer security experts have warned the security included with them was far too weak, or sometimes even nonexistent.

"IoT security has been horribly flawed ever since it first became a thing, largely because of the pace that new products have to go to market, and the fact that designing security is seen by vendors as ‘slowing things down,’" said Casey Ellis, CEO of Bugcrowd, a San Francisco-based computer security service.

This "avalanche" of smart and connected devices has created an environment where software and implementation flaws can be exploited at previously unseen levels, "effectively turning them into widely distributed information weapons," said Mike Ahmadi, director of critical systems security for security company Synopsys.

The danger is two-fold: The devices can be hacked into by one individual and potentially used to enter the owner's home computer network, putting their personal information at risk, or it can be easily taken over and turned into a node on a botnet.

Either way, stronger security would protect both the devices' owners and the larger Internet. However, security is too often left out — and also needs to be continually updated.

While users at least sometimes are willing to install security updates to their phones or computers, the idea of going around and doing software or firmware security updates on thermostats, garage door openers and even refrigerators has yet to catch on.

"The threat research community needs to find a way to prevent the IoT devices from participating in these attacks. They are valuable to the bot army controller because they are usually always on and have high capacity connections that generate huge botnet power," said Jeff Schilling, chief of operations and security at computer security firm Armor.

Read or Share this story: http://usat.ly/2eEBal6 </s> The FBI and Department of Homeland Security are investigating multiple cyber attacks that caused widespread online disruption on both sides of the Atlantic on Friday.

Access to dozens of websites was disrupted and prevented many users from accessing Amazon, Netflix, PayPal, Reddit, Spotify and Twitter.

The cause was a large-scale distributed denial of service attack (DDoS) against Internet performance company Dyn that blocked user access to many popular sites.

It was not immediately clear who was responsible for the outages that started in the Eastern United States spreading to other parts of the country and Western Europe.

Internet traffic company Dyn on Friday warned a third cyberattack is currently ongoing, hours after websites and services across the East Coast were initially shut down.

Dyn told CNBC Friday afternoon the attacks are “well planned and executed, coming from tens of millions of IP addresses at the same time.”

Dyn told CNBC that one of the sources of the attack is coming from devices known as the “Internet of Things” devices such as DVRs, Printers, and appliances connected to the internet.

The company said in a conference call Friday afternoon that the attack is being waged from devices infected with a malware code that was released on the web in recent weeks.

Dyn said it has not heard from attackers and does not know who they are.

“What they’re actually doing is moving around the world with each attack,” Dyn Chief Strategy Officer Kyle York said in a conference call Friday afternoon.

The company’s general counsel, Dave Allen, said during the call the company regularly prepares for scenarios like this.

“We have begun monitoring and mitigating a DDoS attack against our Dyn Managed (Domain Name System) infrastructure. Our Engineers are continuing to work on mitigating this issue,” Dyn said on its website at 11:52 a.m. ET.

A Distributed Denial of Service (DDoS) attack is when a web service is intentionally overwhelmed by traffic from many sources. It is a common method for digital assaults.

Dyn also said the attack impacted its DNS advanced services monitoring for customers, but it later resolved the issue.

It was not known who was behind the distributed denial of service attack.

The Department of Homeland Security told CNBC that it is “looking into all potential causes” of the attack. NBC News reported that one U.S. intelligence official said North Korea had been ruled out as a suspect.

The White House said U.S. authorities are monitoring reports of attack on the internet services company and whether it is a “criminal act,” according to Reuters. </s> This file photo taken on November 7, 2013 shows a banner with the logo of Twitter on the front of the New York Stock Exchange in New York. Major Internet services including Twitter and Spotify suffered outages on Friday as a US Internet provider said it had come under attack (AFP photo)

SAN FRANCISCO — Cyber attacks pounded the underpinnings of the Internet on Friday, crippling Twitter, Netflix and other major websites with the help of once-dumb devices made smart with online connections.

Waves of attacks incapacitated a crucial piece of Internet infrastructure, hampering or outright blocking access to popular online venues.

“When I see something like this, I have to think state actor,” said Carbon Black national security strategist Eric O’Neill, a former “spy hunter” on the FBI counter-intelligence force.

“This is not some hacker sitting in his basement typing away on a keyboard.”

The attack was said to put a troubling new spin on an old hacker attack known as distributed denial-of-service (DDoS), where millions of devices in the fast-growing Internet of things took part in the cyber onslaught.

Armies of computers infected with malicious code are typically used in DDoS attacks intended to overwhelm targets with simultaneous online requests.

Hacker software referred to as Mirai that takes control of IoT devices was evidently linked to the attack, with the broad range of devices making requests helping get past Dyn defences.

“We are seeing attacks coming from a number of different locations,” Level 3 Communications Internet services company Chief Security Officer Dale Drew said in a video posted online.

“We are seeing attacks coming from an Internet-of-things botnet that we identified called Mirai also involved in this attack.”

Heavyweight cyber attacks that seem to yield trouble but no apparent payoff could be probing defences to refine tactics for use on high value targets such as utilities or transportation systems, according to O’Neill and other computer defence specialists.

The attack could also have been meant as a message from a foreign power, cyber security analysts told AFP.

The onslaught commanded the attention of top US security agencies, including the Department of Homeland Security (DHS).

“DHS and the FBI are aware and are investigating all potential causes” of the outages, a spokeswoman said.

The outages left Internet users unable to post messages, shop, watch videos and play games online for parts of the day.

Dynamic Network Services Inc., which manages Internet traffic, said around 1100 GMT that its infrastructure had been hit by a distributed denial of service, or DDoS, attack in the eastern part of the United States.

The initial attack was resolved within about two hours but the company, known as Dyn, was slammed with a second DDoS wave.

DDoS attacks involve flooding websites with more traffic than they can handle, making them difficult to access or taking them offline entirely.

Domain name servers are a crucial element of Internet infrastructure, converting numbered Internet Protocol addresses into the domain names that allow users to connect to Internet sites.

The DDoS attack hit what is akin to a directory assistance service used to route online traffic to the right addresses, meaning that even though networks such as Level 3 were running normally they couldn’t be reached.

A map published by the website downdetector.com showed the effect was felt across the US and into Europe

“The critical point is how fragile our Internet is that these attacks can happen,” O’Neill said.

He worried what damage such attacks might do in less computer security savvy sectors such as finance, energy or transportation.

Dyn put out a status update at 2217 GMT saying the incident had been resolved.

Amazon Web Services, which hosts some of the most popular sites on the Internet, including Netflix and the homestay network Airbnb, said that it also staved off one attack, only to be hit with similar problems several hours later.

DDoS attacks have been in the hacker arsenal for quite some time, but abated as companies learned how to defend against them. Security analysts say there has been a resurgence.

According to Verisign, the number of DDoS attacks rose 75 per cent year-on-year in the second quarter of this year.

Such attacks have escalated “thanks largely to the broad availability of tools for compromising and leveraging the collective firepower of so-called Internet of Things devices — poorly secured Internet-based security cameras, digital video recorders and Internet routers,” cyber security specialist Brian Krebs wrote in a post at krebsonsecurity.com.

Attackers use DDoS attacks for a range of purposes, including censorship, protest and extortion.

The loose-knit hacktivist network Anonymous in 2010 targeted DNS provider EveryDNS and others as retribution for efforts to block the anti-secrecy organisation WikiLeaks.

Roland Dobbins, principal engineer at the networks security company Arbor Networks, told AFP that, though it was spectacular, the attack was a constant and relentless fact of life on the Internet.

“It’s like a combination of the Wild West, Normandy and the Battle of the Bulge on the Internet every day,” he said.

He felt that the attack’s scale did not necessarily mean the attackers had large resources.

“It does not require a nation-state to launch a DDoS attack of this magnitude or impact,” he said. “When it comes to DDoS attacks, states are just another player.”

James Scott, co-founder of the Institute for Critical Infrastructure Technology, said the attacks demonstrated well-known vulnerabilities of the Internet.

“Simply put, the Internet in its original and modern form was not designed with security in mind,” he told AFP. </s> Mirai is a malware that took down a bunch of internet services by breaking into home devices. — Illustration: Wikimedia Commons

On October 21, 2016, a bevy of services suffered internet outage after having been infected by a malware called Mirai that targets smart devices.

Happy about your latest Google Home purchase? Or any other smart home device that makes your life easier by providing you the benefits of the Internet of Things? Well, here's something to be wary of: your trusty automated home devices could be transformed into a malicious army of bots that hold your life ransom.

Sound scary? This is what happened on Friday, as major tech companies like Twitter, Netflix, Reddit, Amazon, Spotify — which are catered to by major DNS service-provider called DYN — suffered malfunctions in their service, an internet outage, because of a malware attack. A DNS essentially helps the computer make sense of a website name by linking it with its IP address.

This malware, now identified as 'Mirai', essentially infects Internet-of-Things devices, floods them with artificial commands and causes them to shut down under a DDoS (distributed denial of service) attack — which means that the devices simply go dead and refuse to perform their functions because of server overload.

DYN said in an interview to CNBC that the "attacks were well-planned and executed, coming from tens of millions of IP addresses at the same time".

Mirai, FYI, has been known to have been responsible for the recent massive attack on cybersecurity news outlet KrebsOnSecurity. It is a botnet malware that was created by someone with the alias of Anna-Senpai, a name that is believed to be a reference to a Japanese novel series Shimoseka, which depicts a dystopian policed world somewhat like George Orwell's 1984.

How does Mirai do its dirty work?

Mirai runs brute-force scans of default usernames and passwords used by the home devices. Usually, owners of these gadgets use very weak login credentials — usernames and passwords — either because they prioritise ease-of-use and convenience or because of the apparently harmless nature of home appliances.

Once the botnet identifies devices that still use default login credentials, it takes control of the gadget and proceeds to pump forged user requests into the service's network, causing its server to shut down and the website to go offline.

Mirai can affect a bunch of IoT devices, including CCTV cameras, TV video-recorder or even your digital refrigerator.

Who could be responsible for the attack?

It is anybody's guess, really. Because, the Mirai source code was recently leaked and made publicly available by Anna-Senpai on Hackforums, according to KrebsOnSecurity.

What can owners of smart devices do now?

Well, as with most things under the sun, you can reboot your device. But be warned, the botnets are so industrious that they are running scans constantly. So, it is highly likely that your device could be infected again the moment it reboots.

According to ISP and telco Level 3, users may be advised to upgrade their devices and set strong passwords for starters, thereby making it harder for Mirai and other such IoT botnets to crack hack into them. Another way is for ISPs to set up protection against 'spoofing', which is what the botnet does when it impersonates the users and spurts out a flurry of nonsensical commands and floods the traffic. </s> Attackers controlling a vast collection of internet devices unleashed several massive attacks on Friday that left dozens of popular websites, including Twitter Inc. and Netflix Inc., unreachable for parts of the day.

Web-technology provider Dynamic Network Services Inc., known as Dyn, said its domain-name-system services were subject to a massive denial-of-service attack starting at 7:10 a.m. EDT on Friday. After the first onslaught was resolved, Dyn reported another wave of attacks that caused disruptions through the day.

... </s> Withering cyberattacks on server farms of a key internet firm repeatedly disrupted access to major websites and online services including Twitter, Netflix and PayPal across the United States on Friday. The White House called the disruption malicious and a hacker group claimed responsibility, though its assertion couldn’t be verified.

Manchester, New Hampshire-based Dyn Inc. said its data centers were hit by three waves of distributed denial-of-service attacks, which overwhelm targeted machines with junk data traffic. The attacks, shifting geographically, had knock-on effects for users trying to access popular websites across the U.S. even in Europe.

“The complexity of the attacks is what is making it so difficult for us,” said Kyle York, the company’s chief strategy officer. “What they are actually doing is moving around the world with each attack.” He said an East Coast data center was hit first; attacks on an offshore target followed later.

The data flood came from tens of millions of different Internet-connected machines — including increasingly popular but highly insecure household devices such as web-connected cameras. It was an onslaught whose global shifts suggested a sophisticated attacker, though Dyn said it had neither suspect nor motive.

The level of disruption was difficult to gauge, but Dyn serves some of the biggest names on the web, providing the domain name services that translate the numerical internet addresses into human-readable destinations such as “twitter.com.”

Steve Grobman, chief technology officer at Intel Security, compared an outage at a domain name services company to tearing up a map or turning off GPS before driving to the department store. “It doesn’t matter that the store is fully open or operational if you have no idea how to get there,” he said in a telephone interview.

Jason Read, founder of the internet performance monitoring firm CloudHarmony, owned by Gartner Inc., said his company tracked a half-hour-long disruption early Friday in which roughly one in two end users would have found it impossible to access various websites from the East Coast.

“We’ve been monitoring Dyn for years and this is by far the worst outage event that we’ve observed,” said Read.

Dyn provides services to some 6 percent of America’s Fortune 500 companies, he said. A full list of affected companies wasn’t immediately available but Twitter, Netflix, PayPal and the coder hangout Github said they experienced problems.

Members of a shadowy collective that calls itself New World Hackers claimed responsibility for the attack via Twitter. They said they organized networks of connected “zombie” computers called botnets that threw a staggering 1.2 terabits per second of data at the Dyn-managed servers.

“We didn’t do this to attract federal agents, only test power,” two collective members who identified themselves as “Prophet” and “Zain” told an AP reporter via Twitter direct message exchange. They said more than 10 members participated in the attack. It was not immediately possible to verify the claim.

Dyn officials said they have received no claim of responsibility, but are working with law enforcement.

The collective, @NewWorldHacking on Twitter, has in the past claimed responsibility for similar attacks against sites including ESPN.com in September and the BBC on Dec. 31. The attack on the BBC marshaled half the computing power of Friday’s onslaught.

The collective has also claimed responsibility for cyberattacks against Islamic State. The two said about 30 people have access to the @NewWorkdHacking Twitter account. They claim 20 are in Russia and 10 in China. “Prophet” said he is in India. “Zain” said he is in China. The two claimed to their actions were “good,” presumably because they highlighted internet security problems.

Another collective member the AP previously communicated with via direct message called himself “Ownz” and identified himself as a 19-year-old in London. He told the AP that the group — or at least he — sought only to expose security vulnerabilities.

During the attack on the ESPN site, “Ownz” was asked if the collective made any demands on sites it attacked, such as demanding blackmail money. “We will make one demand actually. Secure your website and get better servers, otherwise be attacked again,” he said.

For James Norton, the former deputy secretary at the Department of Homeland Security who now teaches on cybersecurity policy at Johns Hopkins University, the incident was an example of how attacks on key junctures in the network can yield massive disruption.

“I think you can see how fragile the internet network actually is,” he said.

Dyn officials said attacks stemmed from tens of millions of devices connected to the internet — closed-circuit video cameras, digital video recorders and even thermostats — that were infected with malware.

“The Internet of Things sort of ran way ahead of how the Internet was architected,” Dyn’s York said on a call with reporters. He said there are between 10-15 billion such devices online.

Dyn first became aware of an attack around 7 a.m. local time, focused on data centers on the East Coast of the U.S. Services were restored about two hours later. But then attackers shifted to offshore data centers, and problems continue.

“It is a very smart attack. As we start to mitigate they react and start to throw something that’s over the top,” York said on a call with reporters.

The second attack broadened its net, affecting the U.S. West Coast. “Prophet” of New World Hackers said hacktivists of the broad, more amorphous Anonymous collective piled on in the third wave on Friday afternoon.

“We’ve stopped all our attacks,” he said at midafternoon. The U.S. Department of Homeland Security was monitoring the situation, White House spokesman Josh Earnest told reporters Friday. He said he had no information about who may be behind the disruption.

Security experts have recently expressed concern over increasing power of denial-of-service attacks following high-profile electronic assaults against investigative journalist Brian Krebs and French internet service provider OVH .

In a widely shared essay titled “Someone Is Learning How to Take Down the Internet,” respected security expert Bruce Schneier said last month that major internet infrastructure companies were seeing a series of worrying denial-of-service attacks.

“Someone is extensively testing the core defensive capabilities of the companies that provide critical internet services,” he said.

Satter reported from London, Bajak from Houston. Bree Fowler in Baltimore, Maryland, contributed to this report. </s> Social network Twitter, music-streamer Spotify, discussion site Reddit and The Verge news site were among the companies whose services were reported to be down on Friday morning.

Amazon.com Inc's web services division, one of the world's biggest cloud computing companies, also disclosed an outage that lasted several hours on Friday morning. Amazon could not immediately be reached for comment.

It was unclear who was responsible for the Dyn attack, which the company said disrupted operations for about two hours.

It is the latest in an increasingly menacing string of "denial of service" attacks disruptinginternet sites by overwhelming servers with web traffic. The U.S. Department of Homeland Security warned on Oct. 14 that hackers were infecting routers, printers, smart TVs and other connected devices to build powerful armies of "bots" that can shut down websites.

Doug Madory, director of internet analysis at Dyn, told Reuters he was not sure if the outages at Dyn and Amazon were connected.

“We provide service to Amazon but theirs is a complex network so it is hard to be definitive about causality at the moment,” he said.

Salesforce.com Inc's Heroku cloud-computing service platform, which runs on Amazon Web Services, disclosed a service outage that it said was related to a denial of service attack "against one of our DNS providers."

Dyn said it was still trying to determine how the attack led to the outage.

"Our first priority over the last couple of hours has been our customers and restoring their performance," Dyn Executive Vice President Scott Hilton said in a statement.

He said the problem was resolved at about 9:20 a.m. EDT (1320 GMT). It earlier reported its engineers were working to respond to an "attack" that mainly affected users on the East Coast.

An FBI representative said she had no immediate comment.

Dyn is a Manchester, New Hampshire-based provider of services for managing domain name servers (DNS), which act as switchboards connecting internet traffic. Requests to access sites are transmitted through DNS servers that direct them to computers that host websites.

Dyn's customers include some of the world's biggest corporations and Internet firms, such as Pfizer, Visa, Netflix and Twitter, SoundCloud and BT.

Attacking a large DNS provider can create massive disruptions because such firms are responsible for forwarding large volumes of internet traffic.
Security analysts state that the October 21 denial-of-service attacks on Internet performance management company Dyn was perpetrated using Mirai malware-created botnets that used consumer internet of things (IoT) smart devices, such as digital video recorders, cable set-top boxes, routers, etc. Technology experts warn that the security included with IoT is weak, or sometimes even nonexistent.