In a report released today, researchers from Group-IB said they discovered the WinRAR zero-day being used to target cryptocurrency and stock trading forums, where the hackers pretended to be other enthusiasts sharing their trading strategies.
These forum posts contained links to specially crafted WinRAR ZIP or RAR archives that pretended to include the shared trading strategy, consisting of PDFs, text files, and images.
I see an "invest in bitcoin" and I immediately think caveat emptor.