Researchers at Bitdefender have been tracking a bit of complex rootkit malware called Zacinlo that they suspect has been operating virtually undetected for over six years. Bogdan Botezatu is a senior cyber security analyst with Bitdefender, and he describes what they've found.

Research link:

https://labs.bitdefender.com/2018/06/six-years-and-counting-inside-the-complex-zacinlo-ad-fraud-operation/