Fileless malware is a malicious code that infects a system’s memory instead of the hard drive. The code is injected into a program such as notepad.exe or javaw.exe. The infected program is then used to exploit an operating system.
The first fileless malware attack was detected in 2012. Today, cybersecurity professionals have detected malicious code in online systems of hundreds of banks, government institution, and telecommunication companies.
A typical fileless malware leaves little traces behind. The malicious code may remain hidden for years without detection.
Fileless malware typically infects system tools such as Windows Management Instrumentation (WMI) and PowerShell. The code will take control of the tools to perform malicious activities without detection.
WMI is used to perform different tasks such as installing software, gathering metrics, and generating queries for the system. The tool can access every system resource and perform functions such as deleting, moving, or copying files. These features make it a dangerous tool when infected by malicious codes.
PowerShell is the scripting language that is used to gain access to the inner core of the machine. The tool is trusted by security software due to which an infection goes undetected. When infected, the tool can be used to run scripts remotely, giving total control of the system to a cybercriminal. The script can be run through WinRM and WMI using a simple code, and it can be used to infect an entire enterprise.