SINGAPORE: If you sense that your computer may be acutely slowing down, take note and check if it has been hijacked to secretly mine for a cryptocurrency known as Monero, IT security company Fortinet warned.
In an advisory issued on Wednesday (Nov 8), Fortinet said its FortiGuard Labs researchers have been discovering "more and more" incidents of cybercriminals carrying out browser cryptojacking.
"The more time users spend on the Web pages, the more CPU cycles can be consumed," Fortinet said. "This explains why hackers typically pick illicit video streaming Web sites, where people stay for hours watching movies or TV serials, to plant such scripts."
Singapore's Computer Emergency Response Team (SingCERT) on Thursday also issued an alert on browser-based digital currency mining, saying it has seen an increase in digital mining tools embedded in websites to secretly mine such currency.
It said users will experience a significant decrease in computer performance when visiting these compromised websites, and the digital currency mining tool running in the background could be taking 60 per cent or more of the CPU’s resources.
Browser cryptojacking started last September when this method to mine cryptocurrency within Web browsers surfaced, it said.
The company also said rough calculations by security researchers show that cryptojacking can be lucrative. For instance, hackers targeting popular illicit sites like The Pirate Bay can earn up to US$12,000 per month.
To see if one's computer has been hijacked, Fortinet said users should check their CPU usage and identify the application hogging the computing resources. They can then end the application and restart the Web browser.
Additionally, to prevent further cryptojacking, the company suggested users to install anti-adware Web browser extensions, as well as Web filtering and antivirus tools on their computer. They can also refrain from visiting illicit sites, it added.
SingCERT issued similar suggestions, recommending extensions such as No Coin and minerBlock for the Chrome browser, or NoScripts for Firefox browser.