After Russian hacktivist group Killnet issued a threat to 49 US-based air travel websites, 13 of them were made offline on Monday to prevent the attack, according to Kevin Collier of NBC. Among them were Hartsfield-Jackson International in Atlanta and Los Angeles International Airport – the two busiest airports in US.

Preemptive action was taken after Killnet issued a threat on their Telegram channel naming 49 websites. The group had targetted several US state websites last week, successfully knocking down Colorado’s for more than a day and interrupting Kentucky’s for a short while.

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It was further reported that airport operations were not affected by the websites going offline and it was only a preventive action.

A spokesperson of the Los Angeles International airport confirmed to NBC via email that the website was briefly affected due to the attack.

The email further said, “The service interruption was limited to portions of the public facing website only. No internal airport systems were compromised and there were no operational disruptions.”

Russian hacker group Killnet specialises in form of cyberattacks called Distributed Denial of Service (DDS) in which the target websites’ servers are overwhelmed with artificially generated mass traffic. It results in the websites’ malfunctioning and often knocks them offline for several days. Websites that provide some form of services are usually targetted in DDS attacks.

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Killnet has been extremely effective in conducting these attacks in recent times. They follow a modus operandi where they mass-source hackers for cyberattacks by notifying in advance on their Telegram group. Their plan to attack US air travel websites was shared in the group on Monday, October 10. 

Although news portal reporting the incident reached out to the U.S. Cybersecurity and Infrastructure Agency and the U.S. Department of Transportation, they refused to comment on the issue.