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

Stealth Virus

This virus will be the table on the DOS interrupt that often we know 
with the "interrupt interceptor". capable this virus to control 
instructions DOS level and are usually hidden according to their good name 
or full size. 
Examples of viruses: 
- Yankee.XPEH.4928, 
infect file *. COM and *. EXE; 
Length of 4298 bytes; 
Characteristics: live in the memory, the size of hidden, have triggered 
- WXYC (a category including the boot record is also due to enter stealth kategri 
also included here), an infect Floopy motherboot record; 
Length of 520 bytes; 
Characteristics: live in the memory; size and hidden viruses. 
- Vmem (s): 
Menginfeksi files *. EXE, *. SYS and *. COM; 
Fie 3275 bytes long; 
Characteristics: live in the memory, the size of hidden, in the encryption.