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https://github.com/vxunderground/MalwareSourceCode
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68 lines
864 B
NASM
68 lines
864 B
NASM
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; A pseudo random numbers generator
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; for use with the MuTation Engine <tm>
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; Version 1.01 (26-10-91)
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; (C) 1991 CrazySoft, Inc.
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.model tiny
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.code
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public rnd_init, rnd_get, rnd_buf, data_top
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rnd_init:
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push ds si dx cx bx
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xor ah,ah
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int 1ah
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in al,[40h]
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mov ah,al
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in al,[40h]
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xor ax,cx
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xor dx,ax
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push cs
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pop ds
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mov si,offset rnd_buf
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xor bh,bh
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jmp short rnd_put
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rnd_get:
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push ds si dx cx bx
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push cs
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pop ds
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mov si,offset rnd_buf
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mov bl,[si]
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xor bh,bh
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mov ax,[bx+si+2]
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mov dx,[bx+si+4]
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add byte ptr [si],4
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mov cx,7
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rnd_lup:
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shl ax,1
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rcl dx,1
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mov bl,al
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xor bl,dh
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jns nxt_bit
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inc al
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nxt_bit:
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loop rnd_lup
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rnd_put:
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mov bl,[si+1]
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mov [bx+si+2],ax
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mov [bx+si+4],dx
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add bl,4
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mov [si+1],bl
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mov al,dl
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cmp bl,[si]
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jnz rnd_done
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add byte ptr [si],4
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rnd_done:
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pop bx cx dx si ds
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ret
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.data
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rnd_buf dw 129 dup(?)
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data_top:
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end
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