WSI Virus

Virus Name: WSI Aliases: WSI.853 V Status: New Discovered: December, 1996 Symptoms: .COM file growth; decrease in available free memory Origin: Unknown Eff Length: 853 Bytes Type Code: PRhCK - Parasitic Resident .COM Infector Detection Method: NAV, NAVDX, AVTK, NAV/N, AVTK/N Removal Instructions: Delete infected files General Comments: The WSI or WSI.853 virus was received in December, 1996. Its origin or point of isolation is unknown. WSI is a memory resident, fast infector of .COM files, including COMMAND.COM. When a program infected with the WSI virus 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 2,048 bytes. Interrupts 09 and 21 will be hooked by the virus in memory. Once the WSI virus is memory resident, it will infect .COM files when they are executed or opened, but not when copied. Infected files will have a file length increase of 853 bytes with the virus being located at the end of the file. The following text strings are visible within the viral code: "Welcome to WSI Opole" "stay cool it's only..." "�V I R U S !!!" The file's date and time in the DOS disk directory listing will not be altered.