Security administrator John Smith has noticed abnormal amounts of traffic coming from local computers at...

https://www.mcafee.com/enterprise/en-us/security-awareness/ransomware/what-is-fileless-malware.html

Fileless malware can easily evade various security controls, organizations need to focus on monitoring, detecting, and preventing malicious activities instead of using traditional approaches such as scanning for malware through file signatures.Also known as non-malware, infects legitimate software, applications, and other protocols existing in the system to perform various malicious activities.It resides in the system’s RAM. It injects malicious code into the running processes. (P.966/950)