Fly 1.1 Virus

Virus Name: Fly 1.1 Aliases: V Status: Rare Discovered: April, 1993 Isolated: Unknown Symptoms: .COM & .EXE growth; write protect errors on diskettes; decrease in total system & available free memory Origin: Unknown Eff Length: 1,771 - 1,786 Bytes Type Code: PRhAK - Parasitic Resident .COM & .EXE Infector Detection Method: F-Prot, Sweep, NAV, IBMAV, AVTK, ViruScan, NAVDX, VAlert, PCScan, ChAV, NShld, Sweep/N, NAV/N, AVTK/N, IBMAV/N, Innoc Removal Instructions: Delete infected files General Comments: The Fly 1.1 virus was submitted in April, 1993. Its origin or point of isolation is unknown. Fly 1.1 is a memory resident infector of .COM and .EXE programs, including COMMAND.COM. When the first Fly 1.1 infected program is executed, the Fly 1.1 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 3,200 bytes. Interrupt 21 will be hooked by Fly 1.1 in memory. Once the Fly 1.1 virus is memory resident, it will infect .COM and .EXE programs, including COMMAND.COM, when they are executed. Infected programs will have a file length increase of 1,771 to 1,786 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 encrypted within the Fly 1.1 viral code: "Fly 1.1" "Sp-5.0" Systems infected with the Fly 1.1 virus will experience write protect errors when the user attempts to execute programs from write protected diskettes when the virus is memory resident.