Lesson 2: Virus Catagories
Multi-partite viruses
Multi-partite or polypartite viruses infect both the boot sector and files on the system. This virus is basically a hybrid of File Infector and Boot sector, making it a very tough virus to clean. If you clean the boot sector without cleaning the files you end up re-infecting your boot sector when an infected file is activated. If you clean your files without cleaning your boot sector you end up re-infecting files the next time you boot. When infected with a multi-partite virus both the boot sector and infected files must be cleaned at the same time.
An example of a multi-partite virus is One_Half also known as Slovak Bomber, Freelove, or Explosion-II. One_Half also has polymorphic capabilities, meaning it has the capability of changing its appearance after each infection, which makes it difficult for virus detection programs to spot it. One_Half was designed to slowly encrypt your hard drive, but while that is happening the user is not aware of it because the virus also decrypts it as the user accesses it. The real damage comes if One_Half is deleted from the system without backup, once the virus is gone the data is encrypted and there is no way to decrypt it.
