Virus.DOS.Natas (Satan spelled backwards), also known as Little Loc or Priest, is a memory-resident stealth virus and is highly polymorphic, that affects files .COM and also .EXE programs.[1]


The virus first appeared in Mexico City in May 1992, spread by a consultant using infected floppy disks. The virus became widespread in Mexico and the southwest United States, although the virus also made its way to the other side of the USA, infecting computers at the United States Secret Service knocking their network offline for approximately three days. This led to an investigation of Priest and incorrect suspicion that the virus specifically targeted government computers.

Natas also infected computers in Canada, England, Russian Federation and Brazil.