Ghostery Extension protects against stealthy cryptocurrency mining

January 29, 2018By Bjoern Greif

The built-in ad blocker within the Ghostery Extension not only reliably blocks unwanted ads. It also prevents websites from secretly hijacking your computer’s resources to mine cryptocurrencies. Some website operators are already using this new method to generate revenue.

Even on YouTube you are not safe from stealthy cryptocurrency mining. Several ads on Google’s video platform ran a mining script in the background that used the computing power of visitors to mine the Monero cryptocurrency. The ads were online for about a week, according to Ars Technica. Ghostery users with activated ad blocker are protected against this.

The mining of cryptocurrencies like Bitcoin, Ethereum, Litecoin, Monero or Zcash has become a real hype. But what are cryptocurrencies? They are based on the idea of a mostly decentralized, distributed and cryptographically secured payment system. Cryptocurrencies are not managed centrally by a bank, but exclusively by private individuals and transferred directly between individual users using the peer-to-peer method.

To dive into the complex functioning of cryptocurrencies in detail would take us too far afield. However, it’s important to understand that a huge amount of processing power is required for crypto mining. Some website operators try to obtain the needed processing power by using the system resources of their website’s visitors.

A prominent example is The Pirate Bay. In September, the torrent tracker had installed a Coinhive script on its website, which uses the CPU power of visitors to mine the Monero cryptocurrency. Since the The Pirate Bay operators had failed to point out the experiment, many puzzled users complained at Reddit about an unusually high CPU workload when visiting the site.

Ghostery’s ad blocker uses a filter list which contains scripts like Coinhive’s. These scripts are blocked automatically so that they cannot tap into your CPU’s processing power without your knowledge. The filter list will be expanded in the future as new mining scripts come to light.