DHAKA: Liberia has been repeatedly cut off from the internet by hackers targeting its only link to the global network.

Recurrent attacks on November 3 flooded the cable link with data, making net access intermittent.

Researchers said the attacks showed hackers trying different ways to use massive networks of hijacked machines to overwhelm high-value targets.

Experts said Liberia was attacked by the same group that caused web-wide disruption on 21 October.

Those attacks were among the biggest ever seen and made it hard to reach big web firms such as Twitter, Spotify and Reddit.

The attacks were the first to send overwhelming amounts of data from weakly protected devices, such as webcams and digital video recorders that had been enrolled into what is known as a botnet.

A botnet variant called Mirai was identified by security firms as being the tool used to find and compromise the insecure devices.

The source code for Mirai has been widely shared and many malicious hacker groups have used it to seek out vulnerable devices they can take over and use to mount what are known as Distributed Denial of Service (DDoS) attacks.

“There are multiple different botnets, each with a different owner,” security researcher Kevin Beaumont told the BBC. “Many are very low-skilled. Some are much better.”

For more than two weeks, my internet has not been working properly. At first I thought it was a problem with my internet provider, which often suffers from slow speeds. But this feels more serious.

Even when you do get online, the connection repeatedly cuts out. I have spent the past week trying to upload some photos and audio to send to London, without success.

Net access in Liberia comes via an undersea cable whose capacity is shared with many other nations in West Africa.

“They are trying a number of different techniques for short bursts, against the companies who own the submarine cable to Liberia,” said Beaumont, adding that commands to botnet#14 seemed to originate in the Ukraine.

Beaumont said the controllers of botnet#14 were refining their control of the attack system but it was not yet clear who it would be turned against next.

A Twitter account, called #Miraiattacks has been set up by a security company to monitor the many different attack targets hit by Mirai botnets. Earlier targets included computer security firms, schools, food-ordering services and gaming sites.

BDST: 2052 HRS, NOV 04, 2016
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