![]() ![]() ![]() PUSH 0 Edit" and write some text in the ascii box as to what you want your Msgbox to say, after unticking "fix to size". ![]() ![]() We need to push the parameters on the stack, then call the function, since memory reads downwards, you cant call a function without having the parameters in place first! All we have to do is put a call to the messagebox with those parameters into our codecave. It would look like for us: MessageBox(0,"Hello",0,0) - very simple parameters. For this example we'll be using the Messagebox function. So, we're going to use this space to put in some custom code. When you get to your address in Olly, scroll down the list until you find a codecave, as seen in the following screenshot: Then go to this address in olly by right clicking and going to Goto -> Expression, then put the address in the box and it will go to it. For DragonNest, the entry address is currently 0x013D3000. In our case, we want this because we are going to call a function right when the game begins, using a codecave. Do this by opening cheat engine and pressing "Memory view", the first address it shows in the top window will be its entry. What we want to do is find what address the game starts at. You should then see a ton of stuff in Olly's windows - this is the process' addresses and instructions, and alot more. Then run your desired process and go to File -> Attach on Olly's menu, and attach it to your process. By combining these two things we can successfully modify the code of many programs, including online games, by redirecting the flow of execution and jumping to our own instructions that we write into a codecave. A codecave allows us to write our own code into its space, since nothing important is really occupying it. A rough description of a codecave would be a bunch of addresses usually set with a value of 0 (add ,al) in succession - basically an area with a bunch of unused memory. Using Ollydbg, we can modify a program's instructions, and redirect flow of execution. ![]()
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