Quasar [1] is an open source RAT (Remote Administration Tool) with a variety of functions. This is easy to use and therefore exploited by several APT actors. JPCERT/CC has confirmed that a group called APT10 used this tool in some targeted attacks against Japanese organisations. As Quasar’s source code is publicly available, there are many variants of this RAT seen in the wild (referred to as “Quasar Family” hereafter). Some...