3Y Virus

Virus Name: 3Y Aliases: 3Y.853 V Status: New Discovery: July, 1994 Symptoms: .COM file growth; decrease in total system & available free memory Origin: Unknown Eff Length: 853 Bytes Type Code: PRhC - Parasitic Resident .COM Infector Detection Method: F-Prot, IBMAV, AVTK, Sweep, ViruScan, NAV, NAVDX, VAlert, PCScan, AVTK/N, Sweep/N, IBMAV/N, NProt, NShld, NAV/N Removal Instructions: Delete infected files General Comments: The 3Y virus was received in July, 1994. Its origin or point of isolation is unknown. 3Y is a memory resident infector of .COM files, but not COMMAND.COM. When the first 3Y infected program is executed, the 3Y 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 1,328 bytes. Interrupt 21 will be hooked by the virus in memory. Once the 3Y virus is memory resident, it may infect .COM files when they are executed, though it does not infect all .COM files. Infected programs will have a file length increase of 853 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 strings are visible within the viral code in all infected files: "COMMAND." "3Y_06b.COM Ver0.6b Copyright 1992 3Y2H" "R3Y_06a.EXE" It is unknown what 3Y does besides replicate.