Ryazan Virus

Virus Name: Ryazan Aliases: V Status: Rare Discovery: December, 1992 Symptoms: .EXE file growth Origin: USSR Eff Length: 512 Bytes Type Code: PRaE - Parasitic Resident .EXE Infector Detection Method: AVTK, Sweep, F-Prot, ViruScan, IBMAV, PCScan, NAV, NAVDX, VAlert, ChAV, Sweep/N, NShld, Innoc, NProt, AVTK/N, IBMAV/N, NAV/N, LProt Removal Instructions: Delete infected files General Comments: The Ryazan virus was submitted in December, 1992 and is originally from the USSR. Ryazan is a memory resident infector of .EXE programs. When the first Ryazan infected program is executed, the Ryazan virus will install itself memory resident in a "hole" in allocated system memory at 0010. It will have hooked interrupt 21. Total system and available free memory, as indicated by the DOS CHKDSK program, will not be altered. Once the Ryazan virus is memory resident, it will infect .EXE programs, other than very small ones, when they are executed. Infected programs will have a file length increase of 512 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 string is encrypted within the Ryazan viral code in infected programs: "!!Ryazan" It is unknown if Ryazan does anything besides replicate.