Instead of being a browser hijacker or adware application, OfferCore acts as the vehicle delivering such PUPs (Potentially Unwanted Programs) to the users' Mac devices. It falls into the category of dubious applications known as bundlers. Their core task is to package an additional program, such as the aforementioned PUPs, alongside a legitimate and more popular software product. Afterward, when the users install the desired application, they also allow the intruder application also to be established on the Mac inadvertently. Typically, the PUP can be found as a preselected choice tucked away under the 'Advanced' or 'Custom' settings of the installation menu.
Bundlers employ various clickbait or misleading tactics to spread themselves. OfferCore, in particular, has been observed to be offered on sites distributing cracked or pirated software. Most often, users land on such sites while searching the net for a cracked version of a specific video game. While it is active, OfferCore might show additional advertisements and offers. Even if the program featured in these advertisements is legitimate, downloading or installing it via a questionable source such as OfferCore is not advisable.
A peculiar aspect of OfferCore is that it doesn't deliver the desired software product but instead creates a text file named 'Last_Step' on the user's Mac system. The file contains a link that triggers the download of a suspicious file. In some instances, this file has been flagged as a malware threat by anti-malware products.
To clean your system from OfferCore or other suspicious applications that might be lurking on it, use a professional security solution. Perform a thorough scan and remove the detected items.