Mr. D Virus

Virus Name: Mr. D Aliases: V Status: Rare Discovered: July, 1993 Symptoms: .EXE file growth; file date/time changes; decrease in total system & available free memory Origin: Unknown, but possibly Poland Eff Length: 1,536 - 1,550 Bytes Type Code: PRhE - Parasitic Resident .EXE Infector Detection Method: AVTK, F-Prot, Sweep, ViruScan, IBMAV, NAV, NAVDX, VAlert, PCScan, ChAV, Sweep/N, NShld, NProt, AVTK/N, IBMAV/N, Innoc, NAV/N Removal Instructions: Delete infected files General Comments: The Mr. D virus was submitted in July, 1993. Its origin is unknown, but it could possibly be from Poland as it appears to be a later version of the Mr. G virus. Mr. D is a memory resident infector of .EXE programs. When the first Mr. D infected program is executed, the Mr. D 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 1,552 bytes. Interrupts 21 and 2F will be hooked by Mr. D in memory. Once the Mr. D virus is memory resident, it will infect .EXE programs when they are executed. Infected programs will have a file length increase of 1,536 to 1,550 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 have been updated to the current system date and time when infection occurred. The following text string is visible within the viral code in all Mr. D infected programs: "Mr. D" See: Mr. G