More than a half million Windows machines, mostly servers, have been zombified by Monero mining malware spread by a cyber gang that created the biggest mining botnet found to date. This botnet is called Smominru. Several security companies have released their research on this cyber group activity. It is a relatively new gang. Crooks started their operations not earlier than the previous year.
Present-day malware is groundbreaking enough to slip under the radar of traditional defenses. Cybercriminals have plenty of time and resources to test their perpetrating code extensively. The malicious code can then potentially circumvent regular detection mechanisms and raise no red flags for days on end.