Friday 13th virus South African VirusB

Virus
File Infector
Discovery Date 11/01/1987
Length 512 Bytes

Aliases

• SouthAfrican

• VirusB

Friday 13th is a file infecting virus. It does not become memory resident. This virus only infects .COM files. Although it does not infect COMMAND.COM.

Each time an infected file is executed, the virus looks for two other .COM files on the C: drive and one on the A: drive, if found they are infected.

The original Friday 13th COM virus first appeared in South Africa in 1987. Unlike the Jerusalem (Friday the 13th) viruses, it is not memory resident, nor does it hook any interrupts. This virus only infects .COM files, but not COMMAND.COM. On each execution of an infected file, the virus looks for two other .COM files on the C: drive and one on the A: drive, if found they are infected. This virus is extremely fast, and the only indication of propagation occurring is the access light being on for the A: drive, if the current default drive is C:. The virus will only infect a .COM file once. The files, after infection, must be less than 64K in length. On every Friday the 13th, if the host program is executed, it is deleted.

Symptoms

The only indication of propagation occurring is the access light being on for the A: drive, if the current default drive is C:. The files, after infection, must be less than 64K in length. Infected files increase in length by 512 bytes.

On every Friday the 13th, if the host file is executed, it is deleted.

Spread

The only way to infect a computer with a file infecting virus is to execute an infected file on the computer. The infected file may come from a multitude of sources including: floppy diskettes, downloads through an online service, network, etc. Once the infected file is executed, the virus may activate.