am using an old imac with os x version 10.9 and apple's latest operating system.
avast for Mac forum section here http://forum.avast.com/index.php?board=5.0
i did a full system scan with avast and it did not show the infection, and the virus vault remained empty, but what i typed above was in the web history activity, so i know i still have the infection.
avast saved your day and blocked the infection before doing harm to your computer ;)

and we here know nada about Mac so post in Mac forum section…