VERY IMPORTANT

TrendMicro discovered a new exploit kit we named Underminer that employs capabilities used by other exploit kits to deter researchers from tracking its activity or reverse engineering the payloads. Underminer delivers a bootkit that infects the system’s boot sectors as well as a cryptocurrency-mining malware named Hidden Mellifera. Underminer transfers malware via an encrypted transmission control protocol (TCP) tunnel and packages malicious files with a customized format similar to ROM file system format (romfs). These make the exploit kits and its payload challenging to analyze.