Six UK teenagers have been arrested in five towns and cities as part of an operation targeting users of hacking group Lizard Squad’s Lizard Stresser tool.

The tool enables users to

take websites offline for up to eight hours at a time using distributed denial of service (DDoS) attacks to flood web servers or websites with requests, leaving them inaccessible to users.

In a recent DDoS attack on popular UK parenting site Mumsnet, the site received about 17,000 requests per second, compared with its normal hit rate of 50 to 100 requests per second.

Two other teenagers suspected of using the tool were arrested earlier in 2015 in Cardiff and Northolt. The latest arrests were made in Manchester, Huddersfield, Milton Keynes and Northampton. All those arrested have since been released on bail.

Operation Vivarium was co-ordinated by the National Crime Agency (NCA), and involved officers from various police forces and Regional Organised Crime Units (ROCUs).

Those arrested are suspected of maliciously deploying Lizard Stresser, having bought the tool using alternative payment services such as bitcoin in a bid to remain anonymous.

The suspects – all male, whose ages range from 15 to 18 – are believed to have targeted a national newspaper, a school, online gaming companies and a number of online retailers.

According to the NCA, police officers are also visiting around 50 addresses linked to individuals registered on the Lizard Stresser website, but who are not currently believed to have carried out attacks.

A third of the individuals identified are under the age of 20, and the activity forms part of the NCA’s wider work to address younger people at risk of entering into serious forms of cyber crime.

Those receiving visits will be told that DDoS attacks are illegal, can prevent individuals from accessing vital online services, and can cause significant financial and reputational damage to businesses.

They will also be informed that committing cyber crime can result in severe restrictions on their freedom, access to the internet, digital devices and future career prospects.

Engaging cyber criminals

Tony Adams, head of investigations at the NCA’s National Cyber Crime Unit (NCCU) said that by paying a comparatively small fee, tools like Lizard Stresser can cripple businesses financially and deprive people of access to important information and public services.

“This multi-agency operation illustrates the commitment of the NCA and its partners to pursuing people who think they can criminally disrupt important public services or legitimate businesses,” he said.

Adams said one of the NCCU’s key priorities is to engage with those on the fringes of cyber criminality.

“We want to help them understand the consequences of cyber crime and how they can channel their abilities into productive and lucrative legitimate careers” he said.

Read more about DDoS attacks

With approximately 30% of UK businesses reporting that they have suffered a DDoS attack in the past year, the NCA said it would continue working with partners to remind businesses to take steps to protect themselves.

The government’s Cyber Essentials Scheme provides guidance on how to guard against and mitigate threats from cyber crime, the NCA said.

For the past nine months, DDoS attacks have doubled compared with the equivalent periods the year before, according to the latest Akamai security report

While attackers favoured less powerful but longer duration attacks during the second quarter of 2015, the number of dangerous “mega attacks” continued to increase, while the financial and retail sectors continued to be the most highly targeted by DDoS attacks, said the Akamai Q2 2015 State of the Internet Security Report.