Hard Days Virus

Virus Name: Hard Days Aliases: V Status: Rare Discovered: December, 1992 Symptoms: .COM file growth; file date/time changes; decrease in total system & available free memory Origin: Unknown Eff Length: 662 Bytes Type Code: PRhCK - Resident Parasitic .COM Infector Detection Method: AVTK, F-Prot, IBMAV, Sweep, ViruScan, NAV, NAVDX, VAlert, PCScan, ChAV, Sweep/N, NShld, Innoc, NProt, AVTK/N, IBMAV/N, LProt, NAV/N Removal Instructions: Delete infected files General Comments: The Hard Days virus was submitted in December, 1992. Its origin or point of isolation is unknown. Hard Days is a memory resident infector of .COM programs, including COMMAND.COM. It bears some similarity to the Red Diavolyata virus. When the first Hard Days infected program is executed, the Hard Days virus will install itself memory resident at the top of system memory but below the 640K DOS boundary, hooking interrupt 21. Total system and available free memory, as indicated by the DOS CHKDSK program, will have decreased by 960 bytes. Interrupt 12's return will not have been moved. Once the Hard Days virus is memory resident, it will infect .COM programs, including COMMAND.COM, when they are executed. Infected programs will have a file length increase of 662 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 can be found within the viral code in all Hard Days infected programs: "It's hard days night!"