Air_Raid Virus

Virus Name: Air_Raid Aliases: Air_Raid.330 V Status: New Discovery: January, 1996 Symptoms: .COM file growth; decrease in available free memory Origin: Unknown Eff Length: 330 Bytes Type Code: PRhCK - Parasitic Resident .COM Infector Detection Method: NAV, NAVDX, ViruScan, AVTK, F-Prot, IBMAV, ChAV, PCScan, NAV/N, AVTK/N, NShld, IBMAV/N, Innoc Removal Instructions: Delete corresponding .COM files General Comments: The Air_Raid virus was received in January, 1996. Its origin or point of isolation is unknown. Air_Raid is a memory resident infector of .COM files, including COMMAND.COM. When the first Air_Raid 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. Available free memory, as indicated by the DOS CHKDSK program from DOS 5.0, will have decreased by 416 bytes. Interrupt 21 will be hooked by the virus in memory. Once the Air_Raid virus is memory resident, it will infect .COM files when they are executed. Infected .COM files will have a file length increase of 330 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: "AR" "Air Raid" "=rat" "ARt" The "AR" text string can also be found starting in the fourth byte of all infected files. The "Air Raid" text string will be located at the very end of all infected files.