anti debugging code for 64 bit

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patchariadog

Joined: 24 Mar 2013
Posts: 94

patchariadog

I have this code that checks for a debugger in 32 bit programs

Code:

;check for debugger
    
mov eax, [fs:30h]
mov eax, [eax+68h]
and eax, 0x70
test eax, eax
jne .debuggerfound
ret

    .debuggerfound:
    invoke ExitProcess,0

I tried to change all of the eax to rax and use it in a 64 bit program but it always thinks a debugger is running

How would I change this code to 64 bit

Thanks

23 Oct 2013, 15:08

tthsqe

Joined: 20 May 2009
Posts: 730

tthsqe

I do not know, but I do know that

Code:

test eax,eax

is not needed and redundant. Smile

23 Oct 2013, 15:16

patchariadog

Joined: 24 Mar 2013
Posts: 94

patchariadog

Your right it still works with out that, thanks!

23 Oct 2013, 15:42

ACP

Joined: 23 Sep 2006
Posts: 204

ACP

Read TEB documentation or use WinDBG to describe it's fields or just disassemble function code (or just use google). I've posted the code for you in the other thread about debugging api.

23 Oct 2013, 17:33

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