hex editing help

[am632]

Hi I have searched around but cant really find what im looking for - its a very simple idea.

I have a file which I can open in a hex editor - goto an offset which I already know and I want to change the value.

I want a script which I can pre-specify a file and offset and an editbox which I can type in a new two-digit figure which will be the value I want to change.

How can I do this? The gui isnt a problem - i just cant really find much info regards hex editing. the reason I want this is to save me opening the file in a hex editor and searching for the offset everytime I want to change it 'cos its time consuming.

can anyone offer any help in the correct direction please?

thanks

[FireFox]

Hi,

This is simple, open the file in "binary" mode and then edit the offset you want (with File or String funcs)

$hFile = FileOpen("myfile.ext", 16) ;binary mode + read

$hexRead = FileRead($hFile)

FileClose($hFile)

$hexEdited = ... ;process the file

$hFile = FileOpen("myfile.ext", 18) ;binary mode + write
FileWrite($hFile, Binary($hexEdited))
FileClose($hFile)

Br, FireFox.

[Malkey]

Expanding of FireFox's example, here is an example using a function that will HexEdit or binary edit a file.

expandcollapse popup

Local $sFileName = "myfile.ext"
Local $iOffSet   = 4     ; No. of bytes from beginning of file.
Local $iNewBinaryValue = "38"    ; "0x38393938" ; Binary values, or, ASCII hexadeciminal values with, or, without the leading "0x"

Local $Ret = _FileHexEdit($sFileName, $iOffSet, $iNewBinaryValue)
If @error Then
Switch $Ret
Case -1
MsgBox(0, "Error", 'Unable to open file: "' & $sFileName & '"')
Case 1
MsgBox(0, "Error", 'Offset out of bounds')
EndSwitch
Else
ConsoleWrite(FileRead($sFileName) & @LF)
EndIf


Func _FileHexEdit($sFileName, $iOffSet, $sHexNew)
If StringLeft($sHexNew, 2) == "0x" Then $sHexNew = StringTrimLeft($sHexNew, 2)
Local $sEndFile = ""
Local $hFile = FileOpen($sFileName, 16) ;binary mode + read
If $hFile = -1 Then Return SetError(1, 0, -1) ; If error opening file

Local $iFileSize = FileGetSize($sFileName)
If $iOffSet < 1 Or $iOffSet > $iFileSize Then Return SetError(1, 0, 1) ; Check offset size

Local $sBeginFile = FileRead($hFile, $iOffSet - 1) ; Read file from start to $iOffSet -1
If ($iOffSet - 1) + (StringLen($sHexNew) / 2) < $iFileSize Then ; Can not set file pointer beyond EOF.
FileSetPos($hFile, ($iOffSet - 1) + (StringLen($sHexNew) / 2), 0) ; 0 = $FILE_BEGIN) ; Set file pointer to (($iOffSet-1) + No. of bytes in $sHexNew)
$sEndFile = FileRead($hFile) ; Read rest of the file from file pointer to EOF.
EndIf
FileClose($hFile)

Local $hexEdited = ($sBeginFile & $sHexNew & StringTrimLeft($sEndFile, 2)) ; Concatenate beginning of file & $sHexNew & end part of file
If StringLeft($hexEdited, 2) <> "0x" Then $hexEdited = "0x" & $hexEdited ; When offset = 1 there is no leading "0x"

$hFile = FileOpen($sFileName, 18) ;binary mode + write
FileWrite($hFile, Binary($hexEdited))
FileClose($hFile)
Return SetError(0, 0, 1)
EndFunc ;==>_FileHexEdit

[am632]

Hi, thanks guys for these examples - sorry I havnt replied earlier, just been bit busy but will check these out 2nite hopefully when I get a spare bit of time.

Thanks a lot

[water]

Why do you want to hex edit a file at all? What kind of file (exe ...) do you need to edit?

[Mobius]

Why do you want to hex edit a file at all? What kind of file (exe ...) do you need to edit?

How is that even relevant, the users reasons are their own, or else they surely would have provided this information would they not.

Is the use of a hex editor suddenly taboo, you are probably right in your assumption but who cares, they recieved the help and support they needed.

Vlad

[water]

It is relevant. If you have read the forum rules you will know that a few things are forbidden here.

I ask to see if the user has a legitimate reason for what he wants to do.

The user just describes what he wants to do but not why. That's why I ask.

[Mobius]

Let the moderators do their jobs and stop lecturing.

were the support indufficient the op would probably have provided more information that would have led us to understand its intent anyway.

Vlad

[water]

Let the moderators do their jobs and stop lecturing.

Don't try to tell me what I have to do or not!

I'm doing the moderators job (a small part of) because if I feel that a thread is not legitimate I report it to the moderators and let them decide what to do.

BTW: Why do you feel the urge to jump in anyway?

[Mobius]

Its an open forum Dude, my reasons are even less your business than the ops reasons.

Now, I am off to do something constructive with my day, I suggest you do similar.

Vlad

[water]

It's my business as soon as you question what I do and how I do it on this forum!

Off for something constructive (as you suggested)

[czardas]

The fact is that information can be put to either good and bad use. This forum is full of such information, and so is the internet. We try to avoid helping anyone who has bad intentions, and it's a fair question to ask for more details about any thread in Help and Support. However, I think it's bad form to automatically asume malicious intent simply because a question is in some way vague.

Once asked I think it is important that the user responds by providing further information, or else a valid reason for not doing so. It then boils down to a moderator's decision, which should always be final.

[FireFox]

yup, and editing a file is not going to help him automating a game, nor cracking a file...

[Melba23]

Hi all,

If you have suspicions about a question, please just report it so that a Mod can take a look. Entering into public spats as above is unneccessary and unedifying.

M23