Play Tetris Virus

Virus Name: Play Tetris Aliases: V Status: Rare Discovered: December, 1992 Symptoms: .COM file growth; decrease in total system & available free memory Origin: Unknown Eff Length: 552 Bytes Type Code: PRhCK - Parasitic Resident .COM Infector Detection Method: Sweep, AVTK, F-Prot, ViruScan, IBMAV, NAV, NAVDX, VAlert, PCScan, ChAV, Sweep/N, NShld, Innoc, NProt, AVTK/N, NAV/N, IBMAV/N, LProt Removal Instructions: Delete infected files General Comments: The Play Tetris virus was submitted in December, 1992. Its origin or point of isolation is unknown. Play Tetris is a memory resident infector of .COM programs, including COMMAND.COM. This virus has no relationship to the Tetris game or the Tetris game's author. When the first Play Tetris infected program is executed, the Play Tetris virus will install itself memory resident at the top of system memory but below the 640K DOS boundary, hooking interrupt 21. Total system and available free memory, as indicated by the DOS CHKDSK program, will have decreased by 768 bytes. Interrupt 12's return will not be moved. Once the Play Tetris virus is memory resident, it will infect .COM programs, including COMMAND.COM, when they are executed. Infected programs will have a file length increase of 552 bytes with the virus being located at the end of the file. The program's date and time in the DOS disk directory listing will not be altered. The following text string can be found within the viral code in all Play Tetris infected programs: "PLAY TETRIS,HI-HI-HI..."