Pysk Virus

Virus Name: Pysk Aliases: Pysk.1536 V Status: New Discovery: February, 1995 Symptoms: .COM & .EXE growth; decrease in available free memory Origin: Unknown Eff Length: 1,536 Bytes Type Code: PRhAK - Parasitic Resident .COM & .EXE Infector Detection Method: F-Prot, IBMAV, AVTK, Sweep, NAV, NAVDX, VAlert, ViruScan, ChAV, NProt, IBMAV/N, AVTK/N, Sweep/N, NShld, NAV/N, Innoc 4.0+ Removal Instructions: Delete infected files General Comments: The Pysk virus was received in February, 1995. Its origin or point of isolation is unknown. Pysk is a memory resident infector of .COM and .EXE files, including COMMAND.COM. When the first Pysk 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 available memory, as indicated by the DOS 5.0 CHKDSK program, will have decreased by 1,744 bytes. Interrupt 21 will be hooked by the virus in memory. Once the Pysk virus is memory resident, it will infect .COM and .EXE files, including COMMAND.COM, when they are executed. Infected files will have a file length increase of 1,536 bytes. 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 be altered. No text strings are visible within the viral code. It is unknown what the Pysk virus does besides replicate.