Dirty Virus

Virus Name: Dirty Aliases: Lavi V Status: Rare Discovered: September, 1993 Symptoms: .COM file growth; file date/time changes; decrease in total system & available free memory Origin: Italy Eff Length: 483 Bytes Type Code: PRhCK - Parasitic Resident .COM Infector Detection Method: F-Prot, IBMAV, ViruScan, Sweep, AVTK, NAV, NAVDX, VAlert, ChAV, NShld, NProt, Sweep/N, AVTK/N, IBMAV/N, Innoc, NAV/N Removal Instructions: Delete infected files General Comments: The Dirty, or Lavi, virus was submitted in September, 1993. It appears to be from Italy. Dirty is a memory resident infector of .COM programs, including COMMAND.COM. When the first Dirty 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. Total system and available free memory, as indicated by the DOS CHKDSK program, will have decreased by 544 bytes. Interrupt 21 will be hooked by Dirty in memory. Once the Dirty 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 483 bytes with the virus being located at the end of the file. The file's date and time in the DOS disk directory listing will have been changed to a random value, and the seconds field will have been set to "62". The following text string can be found within the viral code in all Dirty infected programs: "HI ! I'm The Dirty Fucker !!"