Virus Name: Arriba
V Status: Rare
Discovery: December, 1992
Symptoms: .COM & .EXE growth; system hangs
Eff Length: 1,590 Bytes
Type Code: PRaA - Parasitic Resident .COM & .EXE Infector
Detection Method: AVTK, F-Prot, ViruScan, Sweep, IBMAV,
NAV, NAVDX, VAlert, PCScan, ChAV,
Sweep/N, NShld, Innoc, NProt, AVTK/N, IBMAV/N,
Removal Instructions: Delete infected files
The Arriba virus was isolated in December, 1992. Its origin is
unknown, and the virus may actually have been written in 1991.
Arriba is a memory resident infector of .COM and .EXE programs,
but not COMMAND.COM.
When the first Arriba infected program is executed, the Arriba
virus will install itself memory resident in available free system
memory at 9000, hooking interrupts 21 and 24. Total system and
available free memory, as indicated by the DOS CHKDSK program, will
not be altered.
Once the Arriba virus is memory resident, it will infect .COM and
.EXE programs when they are executed. Infected programs will have
a file length increase of 1,590 bytes. In the case of .COM programs,
the virus will be located at the beginning of the file. In .EXE
programs, the virus will be located at the end of the file. The
program's date and time in the DOS disk directory listing will not
be altered. No text strings are visible within the viral code.
It is unknown what Arriba does besides replicate.