Satan Bug Natas Virus
Satan Bug Natas, or S_Bug, is a highly Polymorphic virus that has been reported to be in the wild in USA and in several other locations. Virus stays resident in memory occupying 9 KB of DOS memory. It hooks the following INT 21h functions: 3Dh, 4Bh, and 6Ch. Infected files grow in size between 4k and 5k bytes. Infected EXE and overlay files may fail to execute correctly. Virus includes string Satan Bug virus - Little Loc. The virus will only become resident if the environment variable COMSPEC= is set to point to a file called COMMAND.COM. S-Bug virus also removes validation codes added to files by McAfee SCAN and CPAV's Immunize function.