Stealth virus

What is stealth virus?
A stealth virus is a hidden computer virus that attacks operating system processes and prevents typical virus or anti-malware scans. Stealth viruses hide in files, partitions and boot sectors and are adept at deliberately avoiding detection.

Stealth Virus eradication requires advanced anti-virus software or a clean system restart.
Stealth viruses hide corrupted computer data and other harmful control functions in system memory and copy themselves into undetectable areas of the computer, effectively fooling antivirus software. To prevent detection, stealth viruses also modify themselves in the following ways:

Code change: The stealth virus changes the code and virus signature of every infected file.

Encryption: The stealth virus encrypts data using simple encryption and uses a different encryption key for each infected file.

Brain, the first stealth virus, spread internationally in the mid-1980s.