Tver-308 Virus

Virus Name: Tver-308 Aliases: V Status: New Discovered: June, 1993 Symptoms: .COM file growth; file date/time changes Origin: Unknown Eff Length: 308 Bytes Type Code: PRaCK - Parasitic Resident .COM Infector Detection Method: F-Prot, AVTK, IBMAV, ViruScan, PCScan, Sweep, NAV, NAVDX, VAlert, ChAV, AVTK/N, NShld, Sweep/N, NProt, IBMAV/N, Innoc, NAV/N, LProt Removal Instructions: Delete infected files General Comments: The Tver-308 virus was submitted in June, 1993. Its origin or point of isolation is unknown. Tver-308 is a memory resident infector of .COM programs, including COMMAND.COM. When the first Tver-308 infected program is executed, the Tver-308 virus will install itself memory resident in a "hole" in allocated system memory, hooking interrupt 21. Total system and available free memory, as indicated by the DOS CHKDSK program, will not be altered. Once the Tver-308 virus is memory resident, it will infect .COM programs when they are executed. Infected programs will have a file length increase of 308 bytes with the virus being located at 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 Tver-308 infected programs: "G.J.V. Tver 1991"