The exponential rise of cryptojacking incidents have been raising concerns among authorities in the last several months, prompting a British government agency to issue a warning on April 11 against cases of computer hijacking to illicitly mine cryptocurrencies.

As the Government Communications Headquarters’ technology sector, the UK National Cyber Security Centre (NCSC) posited, cryptojacking may potentially “become a regular source of income for website owners,” underscoring the proliferation of such incidents in its recent report “cyber threat to UK business.”

In the British agency’s report, it cited the rising cases of cryptojacking that have inflicted over 55 percent of businesses across the globe in December, most of which were perpetrated by websites underhandedly mining digital currencies unbeknownst to computer users. In particular, the report singled out Monero as one cryptocurrency that has been more often mined through a JavaScript cryptocurrency miner, Coinhive.

As has been observed in the last several months, not only has cryptojacking attacks increased significantly, they have not once waned since, as over 4,000 websites have been discovered perpetrating unauthorized crypto mining via a plugin designed for users that are visually-impaired. According to the report, “the only way users may notice their devices are being cryptojacked is a slight slowdown in performance,” underscoring that:

“The technique of delivering cryptocurrency miners through malware has been used for several years, but it is likely in 2018-19 that one of the main threats will be a newer technique of mining cryptocurrency which exploits visitors to a website.”

In addition, the UK cyber security division also deduced that:

“The majority of cryptojacking is carried out by cyber criminals, but website owners have also targeted visitors to their website and used the processing power of visitors’ CPUs, without their knowledge or consent, to mine cryptocurrency for their own financial gain.”

However, the agency noted that there are a number of websites that mine digital currencies with the users’ authorization, Salon being one example of such sites. In a previous report released February, the publication provided its readers options to select whether they prefer advertisements or crypto mining as a requirement to access the publication’s content Although at the time, it was only launched as a trial.

In an effort to curb potential cryptojacking, the agency has additionally advised users to install ad blocker extensions to browsers, as well as secure their system with an antivirus software.