ExploreActivity is classified as a PUP (Potentially Unwanted Program) that is spreading across Mac users. The reason for the application to be designated as a PUP is the dubious distribution methods it employs. Instead of relying on users downloading and installing it willingly, ExploreActivity hides its installation process either in a scheme known as bundling or inside fake software installer/updaters. In fact, ExploreActivity has been observed being delivered through a fake Adobe Flash Player installer.
Once established on the user's computer, the application will initiate its two core functionalities - that of an adware program and a browser hijacker. The adware behavior will result in the user being flooded with unwanted and intrusive advertising materials such as pop-ups, banners, surveys, and more. Each displayed advertisement could lead to a questionable third-party website, potentially exposing the user to various security risks.
The browser hijacker part of ExploreActivity will modify specific browser settings - most likely the homepage, new page tab, and the default search engine, to promote a sponsored address. In the vast majority of cases, browser hijackers are used to diverting traffic towards a fake search engine, i.e. one that cannot produce search results on its own. Instead, any search queries conducted by the user will be taken and either redirected to a legitimate engine directly or carried through a redirect chain involving multiple dubious search engines.
PUPs also could have a certain degree of data-harvesting capabilities. It is not uncommon for applications of this type to track and log the user's browsing activities such as visited websites, clicked URLs or conducted searchers. Some even access the geolocation of the device, its IP address and ISP (Internet Service Provider).