Online VSUM - Keyboard Bug Virus

Keyboard Bug Virus

Virus Name: Keyboard Bug Aliases: Keyboard Bug-1596, Kbug V Status: Rare Discovered: January, 1992 Symptoms: .COM & .EXE growth; decrease in total system & available free memory; system hangs; keyboard interference Origin: Unknown Eff Length: 1,598 - 1,620 Bytes Type Code: PRhA - Parasitic Resident .COM & .EXE Infector Detection Method: Sweep, ViruScan, F-Prot, AVTK, ChAV, IBMAV, NAV, NAVDX, VAlert, PCScan, NShld, LProt, Sweep/N, Innoc, NProt, AVTK/N, NAV/N, IBMAV/N Removal Instructions: Delete infected files General Comments: The Keyboard Bug, or Keyboard Bug-1596, virus was submitted in January, 1992. Its origin is unknown. Keyboard Bug is a memory resident infector of .COM and .EXE programs, but does not infect COMMAND.COM. The first time a program infected with Keyboard Bug is executed, the Keyboard Bug virus will install itself memory resident at the top of system memory but below the 640K DOS boundary. Interrupt 12's return will not have been moved. Total system and available free memory, as indicated by the DOS CHKDSK program, will have decreased by 1,616 bytes. Interrupts 01, 03, 1C, and AC will be hooked by the virus in memory. Once the Keyboard Bug virus is memory resident, it will infect .COM and .EXE programs, other than COMMAND.COM, when they are executed. .COM files will have a file length increase of 1,620 bytes. .EXE files will have a file length increase of 1,598 to 1,612 bytes in length. In both cases, the virus will be located at the end of the infected program. The file's date and time in the DOS disk directory listing will not have been altered. Systems infected with the Keyboard Bug virus will experience intermittent interference with keyboard input due to the virus adding bursts of random characters to the keyboard buffer. System hangs may also occur, in particular if the user attempts to copy programs using the DOS COPY command. Known variant(s) of Keyboard Bug are: Keyboard Bug-914: A 914 byte variant of the Keyboard Bug virus, this variant will be memory resident in 1,328 bytes at the top of system memory but below the 640K DOS boundary, hooking interrupts 08, 1C, AA, and AC. Keyboard Bug-914 infects .COM programs, other than COMMAND.COM, when they are executed. Infected .COM programs will have a file length increase of 914 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. One text string is encrypted within the viral code: "COMMAND" Origin: Unknown March, 1993. Keyboard Bug.1268: Received in July, 1995, this is a 1,268 byte non-resident version of the Keyboard virus described above. It infects one .COM file located in the current directory, bypassing COMMAND.COM, when an infected program is executed. It will then starting accessing alternatingly drives A: and B:. Beeping may also occur. Programs infected with this variant will have a file length increase of 1,268 to 1,284 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: "????????COM" "*.com * \ \" "COMMAND.COM KeyBoard Error ..." "UFO" System hangs frequently occur when infected programs are executed. The text string "KeyBoard Error ..." may also be displayed as a message on the system monitor. Origin: Unknown July, 1995. Keyboard Bug-1720: A larger version of the Keyboard Bug virus, this variant will be memory resident in 1,728 bytes at the top of system memory but below the 640K DOS boundary, as well as have a 448 byte TSR. Interrupts 01, 03, 1C, and AC will be hooked in high memory, and interrupt 21 will be hooked by the TSR. Infected .COM programs will have a file length increase of 1,744 bytes. .EXE programs will have a file length increase of 1,722 to 1,734 bytes. Keyboard Bug-1724: Another variant of the Keyboard Bug virus, this variant is somewhat similar to Keyboard Bug-1720. It infects .COM and .EXE programs when they are executed, adding 1,724 to 1,759 bytes to their length. The virus is located at the end of infected files. Origin: Unknown October, 1992.