It appears that macOS Sierra is being targeted by denial of service malware attacks. This type of malware at first seems to directly affect computers that are not updated to the latest available version macOS Sierra 10.12.2 and this is focused on attacking Safari and Apple's native application, Mail. From what we can read in the specialized media, we are facing an attack that focuses on two different email accounts: dean.jones9875@gmail.com and amannn.2917@gmail.com. Any email received from either of these two accounts is possibly a carrier of the malware, so we have to delete it unopened.
In the case of being affected by the Safari browser, as shown in the middle 9to5Mac it would be hosted on different websites: such as safari-get [.] com, safari-get [.] net, safari-serverhost [.] com and safari-serverhost [.] net. In these sites it is best not to enter just in case. If we notice something strange on the Mac, the first thing we have to do is run an antimalware. The best thing in all cases is to have common sense and not download everything we find on the net, do not visit dubious sites, do not download programs that are from unofficial sites or install extensions that some websites recommend.
The best way to stay out of the reach of these malware is simply to update the computers as soon as they have the update available and with this we will avoid many problems. On the other hand, we are now concerned that there are more attacks on Mac software and this is not because macOS Sierra is more vulnerable than other versionsIt is simply that there are more and more macOS users so it is "more desirable" for hackers to introduce these advertising malware or similar into the system. In principle, all of us who are in 10.12.2 or in beta versions do not have to worry about it, but it does not hurt to have common sense when downloading or accessing some web pages.