asked on

Changing exe hex values

Is it possible to change the hex values of an EXE like you would with a hex editor?
I know it is possible in C to SEEK hex addresses, but I don't know if this is possbile in vb or not.
Once I've got to the right place by using a hex address, can I then change what ever the program has at that point?
For instance goto 00046D7A in a program and change the code from something like 753C6A006A00 to E93900000090? For instance.
Can you give me some code or some explanations please.

ASKER CERTIFIED SOLUTION

mcrider

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

billy_98_1

ASKER

So, I need to change my hex offset to a decimal. And any thing I want to change I have to change from a hex value to a decimal?
I'm guessing I can add up the hex values in my mind. So A1 would be 11+2 (just so to make sure)?

mcrider

>>So, I need to change my hex offset to a decimal.

You need to change it to decimal+1... Remember, SEEK starts at 1, not 0

>>And any thing I want to change I have to change from a hex value to a decimal?

If for example, you wanted to write the letter "A" which is x41 at a particular byte offset, you would do chr$(65)

Make Sense??

Cheers!®©

mcrider

By the way, you see in the code example above that I am writing the CHR$ like this:

Put #fNum, , Chr$(&H59)

Chr$(&H59) is the same as using Chr$(89)...

Both give you a "Y". &H59 gets converted automatically to a decimal value...

Cheers!®©

billy_98_1

ASKER

Where did x41 come from? I'm guessing 65 is the ascii value for 'A'?

mcrider

the x41 was just an example of an A... for example if you hex dumped a file and saw:

41 6C 6C 65 6E 00

in ascii that would be "Allen"+Chr$(0)

Try this in the debug window... Type:

?chr$(&h41)

You will get an "A" to appear... Type:

?chr$(65)

And you will also get an "A" to appear...

Hopefully this question will get graded with a chr$(&h41) or a chr$(65) or an "A"... 'cause they're all the same...

;-)

Cheers!®©

billy_98_1

ASKER

That's brilliant thanks. You've cleared up a lot for me. This was definitely a chr$(&h41) grade answer.

Thanks again.

mcrider