Using this api structure.... ????

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shism2

Joined: 14 Sep 2005
Posts: 248

shism2

mov eax,"ExitProcess"
mov [blah],eax
invoke GetModuleHandle,0
mov [hInstance],eax
invoke MessageBox,0,flathello,0,0
invoke ExitProcess,0

;+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
align 4

flathello db "Flat hello",0

;+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
align 4

hInstance dd ?
blah dd ?
;=======================================================================
data import

library kernel32,'KERNEL32.DLL',\
user32, 'USER32.DLL'

import kernel32,\
ExitProcess,blah,\
GetModuleHandle,'GetModuleHandleA'
import user32,\
MessageBox,'MessageBoxA'

end data

How could I make that work?

16 Sep 2005, 04:28

Vasilev Vjacheslav

Joined: 11 Aug 2004
Posts: 392

Vasilev Vjacheslav

Code:

format pe gui 4.0
entry start

include '%fasminc%\win32a.inc'

section '.idata' data readable writeable

  szFlatHello db "hello",0

section '.udata' readable writeable

  hInstance dd ?
  hBlah dd ?

section '.code' code readable executable

  start:
mov eax,[ExitProcess]
mov [hBlah],eax
invoke GetModuleHandle,NULL
mov [hInstance],eax
invoke MessageBox,NULL,szFlatHello,NULL,NULL
invoke ExitProcess,NULL

section '.idata' import data readable writeable

  library       kernel32,'kernel32.dll',\
                user32,'user32.dll'

  include       '%fasminc%\apia\kernel32.inc'
  include       '%fasminc%\apia\user32.inc'

; eof

16 Sep 2005, 05:35

shism2

Joined: 14 Sep 2005
Posts: 248

shism2

format PE GUI 4.0
;format PE CONSOLE
;=======================================================================

;=======================================================================

entry start
include '%fasminc%\win32a.inc'

mov eax,[ExitProcess]
mov [hBlah],eax
invoke GetModuleHandle,NULL
mov [hInstance],eax
invoke MessageBox,NULL,flathello,NULL,NULL
invoke ExitProcess,NULL

;+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
align 4

flathello db "Flat hello",0

;+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
align 4

hInstance dd ?
hBlah dd ?
;=======================================================================
data import

library kernel32,'KERNEL32.DLL',\
user32, 'USER32.DLL'

import kernel32,\
ExitProcess,hBlah,\
GetModuleHandle,'GetModuleHandleA'
import user32,\
MessageBox,'MessageBoxA'

end data

This is what I have so far... Im trying to use the object hBlah in the imports.. How could I do that?

16 Sep 2005, 06:03

shoorick

Joined: 25 Feb 2005
Posts: 1608
Location: Ukraine

shoorick

hi!

Quote:

import kernel32,\
ExitProcess,'ExitProcess',\

ExitProcess will be used as label to dword, which will be filled with offset of function 'ExitProcess' in kernel32.dll with loader while loading.

so, what do you wish? to get this offset while runtime is possible with:
mov eax,[ExitProcess]
then you can "invoke" it with
push 0
call eax
for example

16 Sep 2005, 08:01

shism2

Joined: 14 Sep 2005
Posts: 248

shism2

No I wish this part

To Load hBlah into
import kernel32,\
ExitProcess,'LOAD HBLAH INTO HERE',\

Is it possible to do this at runtime..

16 Sep 2005, 18:52

coconut

Joined: 02 Apr 2004
Posts: 326
Location: usa

coconut

dont think that will work if at assembly time hBlah isnt known - what will get written to IAT? what exactly do you want to do?

16 Sep 2005, 19:00

shoorick

Joined: 25 Feb 2005
Posts: 1608
Location: Ukraine

shoorick

maybe you want to do this:

Code:

;=======================================================================
include '%fasminc%\win32a.inc'                                         
;=======================================================================
section '.flat' code readable writeable executable

entry $

    mov  eax,[ExitProcess]
    xchg eax,[MessageBox]
    mov  [ExitProcess],eax
    invoke ExitProcess,0,flathello,0,0
    invoke MessageBox,0

;+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
    align 4

flathello   db "Flat hello",0

;=======================================================================
section '.idata' import data readable writeable

  library kernel32,'KERNEL32.DLL',\
          user32,  'USER32.DLL'

include     '%fasminc%\apia\kernel32.inc'
include     '%fasminc%\apia\user32.inc'
;=======================================================================

- this is working Wink

_________________
UNICODE forever!

16 Sep 2005, 20:26

shism2

Joined: 14 Sep 2005
Posts: 248

shism2

Thats unique shoorick and sort of like that Smile

...

The hblah = exitprocess .... I was thinking of implementing sort of a crypted import table that gets decrypted ...But it seems that it can't use this Sad

Like lets say using this

mov eax,[ExitProcess]
mov [hBlah],eax
invoke GetModuleHandle,NULL
mov [hInstance],eax
invoke MessageBox,NULL,flathello,NULL,NULL
invoke ExitProcess,NULL

;+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
align 4

flathello db "Flat hello",0

;+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
align 4

hInstance dd ?
hBlah dd ?
;=======================================================================
data import

library kernel32,'KERNEL32.DLL',\
user32, 'USER32.DLL'

import kernel32,\
ExitProcess,hBlah,\
GetModuleHandle,'GetModuleHandleA'
import user32,\
MessageBox,'MessageBoxA'

end data

At runtime hblah which is encrypted gets decrypted and allows for the api calls to work...This is just an example TRYING to load 'ExitProcess' into hblah and having hblah in the import table be replaced with ExitProcess

16 Sep 2005, 20:38

Reverend

Joined: 24 Aug 2004
Posts: 408
Location: Poland

Reverend

Imports don't work this way. They are pre-loaded before starting the main code

16 Sep 2005, 21:40

shoorick

Joined: 25 Feb 2005
Posts: 1608
Location: Ukraine

shoorick

maybe you do not understand conception of import enough well:
1.import table exists exactly for normal placing offsets according to dll and function names by loader while loading. if you do not wish to show which functions you are using - hide their names anywhere you want and at runtime decode them and use loadlibrary: all hackers do this.
2.you can of course get once real offsets for functions, encrypt them, and then decrypt at runtime, but offsets can (will!) be differ on other system depending on version/sp/etc - so, this is commonly unusable.
3.if you do not plan to use import table so you do not need to create it at all - you can store offsets to functions wherever you want.

Code:

;=======================================================================
 format PE GUI 4.0
;format PE CONSOLE
;=======================================================================
 include '%fasminc%\win32a.inc'                                         
;=======================================================================
 section '.flat' code import readable writeable executable
;-----------------------------------------------------------------------
  library kernel32,'KERNEL32.DLL'
;-----------------------------------------------------------------------
  import  kernel32,\
    ExitProcess,'ExitProcess',\
    LoadLibrary,'LoadLibraryA',\
    GetProcAddress,'GetProcAddress'
;-----------------------------------------------------------------------
 align 4
messagebox  db 'MessageBoxA',0
 align 4
MessageBox  dd  0EBFEEBFEh
user32      db 'user32.dll',0
;-----------------------------------------------------------------------
@@: entry $
    invoke LoadLibrary,user32
    invoke GetProcAddress,eax,messagebox
    mov [MessageBox],eax
;-----------------------------------------------------------------------
    invoke MessageBox,0,messagebox,user32,0
;-----------------------------------------------------------------------
    invoke ExitProcess,0
;=======================================================================

_________________
UNICODE forever!

16 Sep 2005, 22:12

shoorick

Joined: 25 Feb 2005
Posts: 1608
Location: Ukraine

shoorick

this even more cool Wink

Code:

;-----------------------------------------------------------------------
 align 4
messagebox  db 'MessageBoxA',0
user32      db 'user32.dll',0
;-----------------------------------------------------------------------
 entry $
MessageBox  dd  0C18B02EBh
    invoke LoadLibrary,user32
    invoke GetProcAddress,eax,messagebox
    mov [MessageBox],eax
;-----------------------------------------------------------------------
    invoke MessageBox,0,messagebox,user32,0
;-----------------------------------------------------------------------

16 Sep 2005, 22:27

coconut

Joined: 02 Apr 2004
Posts: 326
Location: usa

coconut

no need to define .flat section, fasm does it for you (and sets entry) if no section defined

16 Sep 2005, 23:41

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