Virus Name: Mario
V Status: New
Discovered: January, 1996
Symptoms: .EXE file growth; TSR
Eff Length: 673 - 689 Bytes
Type Code: PRsE - Parasitic Resident .EXE Infector
Detection Method: F-Prot 2.22+, AVTK 7.60+, IBMAV 2.41D+, ViruScan 2.51+,
NAV 3.09 9607+, NAVBoot 0.A 9607+, PCScan, ChAV,
AVTK/N 7.60+, NAV/N 2.0 9607+, NShld 2.32 9607+,
Removal Instructions: Delete infected files
The Mario or Mario.673 virus was received in January, 1996, along
with one variant, Mario.746. Mario is a memory resident infector
of .EXE files.
When the first Mario infected program is executed, this virus will
install itself memory resident as a low system memory TSR of 992
bytes. Interrupts 18, 21, and 24 will be hooked by the virus in
Once the Mario virus is memory resident, it may infect .EXE files
when they are executed or opened, but not on copy, though it does
not always infect .EXE files it encounters. Programs infected with
the Mario virus will have a file length increase of 673 to 689 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 visible within the viral code:
It is unknown what the Mario virus may do besides replicate.
Known variant(s) of Mario are:
Mario.746: Also received in January, 1996, this is a 746 byte
variant of the Mario virus described above. It becomes memory
resident at the top of system memory but below the 640K DOS
boundary, hooking interrupts 18 and 21. Available free memory,
as indicated by the DOS CHKDSK program from DOS 5.0, will have
decreased by 1,296 bytes. Once resident, this variant may
infect .EXE files when they are executed or opened, but not on
copy. Infected programs will have a file length increase of
746 to 760 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. No text strings are visible within
the viral code.
Origin: Unknown January, 1996.