Polymorphic Virus

This virus is designed for lead on antivirus program, it means the virus is always 
trying to avoid being identified by antivirus is always changing with the change 
structure each time the file is complete menginfeksi / other programs. 
Examples of viruses: 
- Necropolis A / B, 
infect file *. EXE and *. COM; 
The length of the file 1963 bytes; 
Characteristics: live in the memory, the size and hidden virus, encrypted, and can 
changed the structure change 
- Nightfall,Menginfeksi file *. EXE; 
The length of the file 4554 bytes; 
Characteristics: live in the memory, the size and hidden virus, has triggered, 
encrypted and can change the structure