ASM Community

Hi guys.

I wrote this to open a command prompt the hard way  :D,the only problem is it closes straight away.
Can anyone tell me how to keep this open when it runs.
Thanks .

;NASM 
;
;compile with:
;NASM.EXE -fobj msvcrt.asm
;link with:
;ALINK.EXE msvcrt.obj -c -oPE

EXTERN ExitProcess
IMPORT ExitProcess kernel32.dll

segment .code USE32 

..start

push ebp                       ;procedure prolog
mov ebp, esp                   ;
xor eax,eax                    ;make nulls
push eax                       ;put on stack
push eax                       ;
mov dword,6376736dh   ;vcsm
mov word , 7472h      ;tr
mov ecx, 7c590221h             ;offset of loadlibrary 
lea eax,              ;load the msvcrt string into eax
push eax                       ;put it's address onto stack
call ecx                       ;call loadlibray
pop eax                        ;clean stack for later
xor eax,eax                    ;make nulls
push eax                       ;put nulls onto stack
mov dword ,2e646d63h  ;.dmc
mov word ,7865h       ;xe
mov byte ,65h         ;e
mov ecx,78018ebfh	       ;offset for system 
lea eax,              ;load system string into eax
push eax                       ;put it onto stack
call ecx                       ;call system
push ebp                     ;pocedure prolog
mov ebp,esp                ;
push 7c5969beh           ;address of exitprocess
xor eax,eax                 ;make nulls
push eax                    ;
call dword        ;call exit process

Hi Spook.

I tried out the sleep function but had no luck.
The only reason I'm doing it this way is so I can actually learn whats going on.
I'll have another lok around to see if I can find anything .

Thanks alot.

Strictly from memory, which in my case is pretty unreliable, you have to call cmd.exe with the /k switch in order to have it stay open. I will chack to make sure when I get home from work tonight as I use it in WinExplorer, though not the msvcrt version.

comrade

Thats an understanable observation .
Actually come to think of it it does look like shellcode,but thats not what this is.
Simply trying to learn how to call functions and use the stack.

Hi Fodder.

Msvcrt is the dll I'm calling the external functions from.
As I said already im learning the hard way so I know whats going on.
The way I see it is, I used masm for awhile and all I did was call api's using invoke and other macro's and only now I'm learning asm .

If you look at my previous posts I'm learing how the stack works I pushed stings for the messagebox function.

I don't have to use hardcoded addresses, i could use

EXTERN ExitProcess
IMPORT ExitProcess kernel32.dll
EXTERN MessageBoxA
IMPORT MessageBoxA user32.dll

but if I didn't decide to use hardcoded addresses I would still perhaps be in the dark as far as asm coding works without macros and the include files and libs.

Honestly I've learned more from doing it the hard way then 2 months using masm.
So far in the last few days my understanding of fuctions,dll's and the stack has been very enjoyable.

And for any guests or other uses who view the thread, I'm sure there learning things.


Thanks

No problem.

If I had read this post a few days ago I wouldn't have a clue what you were on about.
But since I choose the hard way to do this code now I know what your on about.

Thanks for the suggestions about fasm I will look into that as soon as I understand assembler more.

Thanks for your opinions.

Homer.

I didn't realise my question was like that untill comrad pointed it out.
Thanks alot so far anyways for your help guys.