Grace Virus

Virus Name: Grace Aliases: Grace.1346 V Status: New Discovered: January, 1996 Symptoms: .COM & .EXE growth; decrease in available free memory; system hangs Origin: Unknown Eff Length: 1,346 or more Bytes Type Code: PRhA - Parasitic Resident .COM & .EXE Infector Detection Method: NAV, NAVDX, AVTK, ViruScan, IBMAV, F-Prot, ChAV, NAV/N, AVTK/N, NShld, IBMAV/N, Innoc Removal Instructions: Delete infected files General Comments: The Grace or Grace.1346 virus was received in January, 1996. Its origin or point of isolation is unknown. Grace is a memory resident fast infector of .COM and .EXE files, but not COMMAND.COM. When the first Grace 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. Available free memory, as indicated by the DOS CHKDSK program from DOS 5.0, will have decreased by 5,120 bytes. Interrupt 21 will be hooked by the virus in memory. Once the Grace virus is memory resident, it will infect .COM and .EXE files when they are executed, opened, or copied. Infected .COM files will have a file length increase of 1,346 bytes with the virus being located at the end of the file. .EXE files will increase in size by more than 1,346 bytes, and the virus will be located somewhere between the middle and the end of the file. In both cases, the program's date and time in the DOS disk directory listing will not be altered. The following text strings are visible within the viral code in all infected programs: "-[Grace] by T„L”N 94-" "You make me sick I make viruses" "Have a nice $piss-up!" "DOS!" "DCOSCCLVSF-COMEXE" System hangs may occur when small .COM and .EXE files are executed with the virus memory resident.