Hackers are using different type of apps as a medium for running crypto minning software on computers of users who uses the app. Some websites builders are building websites just for using the power of visitor's device for mining crypto currency (most of the time Monero) however this is not considered non-ethical. This time hackers targeted Browsealoud (free tool for text translation) for injecting coinhive mining malware script into the tool's javaScript code base.
They were successful in infecting almost 4275 government websites who starting mining cryptocurrency for them. They were however quickly caught because they infected some websites which were handled by experts and the found out the malware. As they were caught very early they were only able to made $24. Coinhive consider it ethical to replace the revenue generated by ads with mining software. According to some users it is ethical but it should be in the knowledge of users.