Uruk-hai Virus

Virus Name: Uruk-hai Aliases: V Status: New Discovered: February, 1993 Symptoms: .COM file growth; file date/time changes Origin: USSR Eff Length: 394 Bytes Type Code: PRxCK - Parasitic Resident .COM Infector Detection Method: Sweep, AVTK, F-Prot, IBMAV, ChAV, ViruScan, NAV, NAVDX, VAlert, Sweep/N, AVTK/N, NShld, NProt, IBMAV/N, Innoc, NAV/N, LProt Removal Instructions: Delete infected Files General Comments: The Uruk-hai virus was submitted in February, 1993, and is from the USSR. Uruk-hai is a memory resident infector of .COM progams, including COMMAND.COM. When the first Uruk-hai infected program is executed, this virus will install itself memory resident in a "hole" in low 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 Uruk-hai virus is memory resident, it will infect .COM programs when they are executed. If COMMAND.COM is executed, it will become infected. Programs infected with the Uruk-hai virus will have a file length increase of 394 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 Uruk-hai infected programs: "V 1.0 Igor,1992 The Uruk-hai are upon you!" Known variant(s) of Uruk-hai are: Uruk-hai 300: A 300 byte variant of the Uruk-hai virus described above, this variant also resides in a "hole" in allocated memory, hooking interrupt 21. It infects .COM programs when they are executed, adding 300 bytes to their length. The virus is 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 Uruk-hai 300 infected files: "Igor 1992 v.2.0 The Uruk-hai and winged Nazgul strikes again!" Origin: USSR June, 1993. Uruk-hai 361: A 361 byte variant of the Uruk-hai virus described above, this variant becomes memory resident at the top of system memory but below the 640K DOS boundary, moving interrupt 12's return. Total system and available free memory, as indicated by the DOS CHKDSK program, will have decreased by 1,024 bytes. Interrupt 21 will be hooked by the virus in memory. It infects .COM programs when they are executed, adding 361 bytes to their length. The virus is 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 Uruk-hai 361 infected files: "Igor 1992 v.3.0 It was last assault of the Uruk-hai... We shall meet in Valhalla!" Origin: USSR June, 1993.