F-Secure Virus Descriptions : V-Sign

V-Sign is a typical boot sector virus, except that it uses slightly polymorphic encryption.

V-Sign infects DOS boot sectors on diskettes and Master Boot Records on hard disks. It is only able to infect a hard disk when you boot a machine with an infected diskette in drive A:. At this time the virus infects the Master Boot Record, and after that it will go resident to high DOS memory during every boot-up from the hard disk. Once V-Sign gets resident to memory, it will infect practicly all non-writeprotected diskettes used in the machine.

V-Sign doesn't preserve the original boot sector when it infects a disk. The virus activates after infecting 64 diskettes. At this time it will display a large V-shaped letter and hang the machine.