CMagic Virus

Virus Name: CMagic Aliases: CMagic.2015 V Status: New Discovery: July, 1994 Symptoms: .COM file growth; DOS CHKDSK file allocation errors; decrease in total system & available free memory; sounds from system speaker; file date/time seconds = "62" Origin: Unknown Eff Length: 2,015 Bytes Type Code: PRhCK - Parasitic Resident .COM Infector Detection Method: AVTK, IBMAV, Sweep, ViruScan, F-Prot, NAV, NAVDX, VAlert, PCScan, ChAV, Sweep/N, AVTK/N, NProt, NShld, IBMAV/N, NAV/N, LProt, Innoc 4.0+ Removal Instructions: Delete infected files General Comments: The CMagic, or CMagic.2015, virus was received in July, 1994. Its origin or point of isolation is unknown. CMagic is a memory resident infector of .COM programs, including COMMAND.COM. It is a fast infector which employs some stealth techniques to avoid detection. When the first CMagic infected program is executed, this virus will install itself memory resident at the top of system memory but below the 640K DOS boundary, not moving interrupt 12's return. Total system and available free memory, as indicated by the DOS CHKDSK program, will have decreased by 4,064 bytes. Interrupt 21 will be hooked by the virus in memory. Once the CMagic virus is memory resident, it will infect .COM programs, including COMMAND.COM, when they are executed, opened, or copied. Infected programs will have a file length increase of 2,015 bytes, though the file length increase will be hidden by the virus when it is memory resident. The virus will be located at the end of the file. The program's date and time in the DOS disk directory listing will not appear to be altered, though the seconds field will have been set to "62". The following text string is encrypted within the viral code: "[CMAGiC/fX] By Mnemonix - v1.00 1994" When the virus is memory resident, unexpected sounds may be emitted from the system speaker. The DOS CHKDSK program will indicate file allocation errors on all infected files when the virus is memory resident. Known variant(s) of CMagic are: CMagic.2246: Also received in July, 1994, CMagic.2246 is a later version of the CMagic virus described above. Its size in memory is 4,544 bytes, hooking interrupt 21. Like the original virus, it infects .COM programs, including COMMAND.COM, when they are executed, opened, or copied. Infected programs increase in size by 2,246 bytes, though the file length increase will be hidden when the virus is memory resident. The virus will be located at the end of all infected files. The file's date and time in the DOS disk directory listing will appear to be unaltered, though the seconds field will have been set to "62". The following text string is encrypted within the viral code: "[CMAGiC/fX] By Mnemonix - v1.50 1994" The sound of an ambulance siren may be emitted from the system speaker when the virus is memory resident. The DOS CHKDSK program will indicate file allocation errors on all infected files when the virus is memory resident. Origin: Unknown July, 1994.