PaloAlto Unit 42 researchers have observed a new Remote Access Tool (RAT) constructed by an unknown actor of Italian origin. This RAT, referred to as uWarrior because of embedded PDB strings, has been previously described by an independent researcher who noted a potentially unknown exploit being used against Microsoft Office. Initial research into the exploit by Unit 42 indicates that this actor has opted to include multiple exploits. One is CVE-2012-1856, reinvigorated with a novel ROP chain to bypass ASLR and deliver the uWarrior payload. The other appears to be CVE-2015-1770. The malware itself is a fully featured RAT, which uses a compressed, (optionally) encrypted, raw TCP socket and binary message protocol for command and control communications. During the course of our research, it became evident that this actor had not built uWarrior from scratch, but rather opted to borrow components from several off-the-shelf tools. Linkages between older RATs are explored later in this blog.