I wrote a c++ program and I want to protect it.
I need that the program can run only on authorized computer, and I'd stop the program when I want.
I thought 2 solutions, but I'm not knowing if these are good or easily cracked.
The first solution:
local_mac_address = get_mac_address();
if(local_mac_address == "\* authorized addr */")
return true;
else
return false;
The second solution:
I upload an html page with a secret code on a my website.
page = download_page(url);
if(page == "my_secret_code")
return true;
else
return false;
If I'll change the code in the html source the program won't start.
What do you think about these 2 solution ?
Are they safety?
Edit:
The executable works on my computers in an office, so I want to avoid that someone can copy it and use on theyr computer
I'd say that both of these are easy to circumvent.
The first could be undone by simply preloading a shared library implementing the get_mac_address() function returning the expected result.
The second could easily be defeated by intercepting the network traffic and returning the expected reply.
Additionally, both could easily be disabled after a little work with a debugger, a disassembler and a hexeditor and just modifying the executable to bypass both checks.
Don't spend countless of hours trying to get your program "protected". It's impossible.
The moment that the executable is on the client's computer you have no control over what the client does with it and thus you should use your time working on more useful things for your application. Adding a bit of extra security is never a bad thing but don't make it the main focus point. If someone really wants to gain access, they will.
They are not safe at all.
The thing with protecting programs is that they are files,which can be opened by a disassembler or if you are so pro,with an hex editor.
With an disassembler your little code can be easily removed,and the program will run when the code is removed.
What you can is that you can encrypt the executable and have a decrypter at the start.Your site will give the decrypter the password,gives it another password to encrpyt the exec when it is done running for extra security.
if you put the decrypter at the start,or load the program as data(not exec) the decrypter wont have any problems running.Its called always online DRM.
Related
I'm coding a web server for fun and I'm now trying to make it dynamic.
I need to do the part usually PHP would do in regular web development, be inside the page code and be executed server side while the server runs.
Now, I've been thinking, and reading a bit on this. I could separate it and then invoke the compiler to make that code run, but I've also read that's not a good way to go about it, so I'd like to avoid it.
I thought maybe if I compiled a program that would go with the specific page it was meant to and made it change the page based on arguments and return the page in buffers, it could work, but that just seems cumbersome.
One wouldn't want to include the code for every single page on the webserver because it just doesn't scale well.
I don't believe C++ can do a "CALL" as in batch when the program is running, it would though, I believe, be the ideal solution besides including a file mid program which isn't possible.
I would like to know whether or not there's a way of executing a program or non-included code during runtime and if so how.
You could try dlopen, dlsym, dlerror and dlclose. These allow you to, at runtime, load libraries. Your server could use it to load code which should execute inside a page.
Howto, by Aaron Isotton
Documentation on man7.org
When running my asmjs\emscripten application, compiled from C++, it has suddenly started to log: "run() called, but dependencies remain, so not running" to the web console, and nothing more happens.
I've added some cout's at the absolute start of my main, but even they aren't reached.
The application executed successfully before, but suddenly this started to happen and I don't know what change triggered this.
Does anyone know how to debug this?
Update
After removing as much source code as I could, this happens as soon as I #include , even due my main simply consists of a single cout.
Ideally you would have the entire environment when it was running in version control, and build every version since to see where it broke.
You might have your code in version control, but perhaps not Emscripten itself. If you've updated Emscripten, this could lead to differences in behaviour. I would try going back to whatever version you used when it was running. Note that sometimes various cache directories survive an Emscripten version change, and might need to be cleared manually (I forgot which exactly).
The dependencies remaining could mean that you are trying to do something before Emscripten has loaded any other files it needs to, say files requested by --preload-file or --memory-init-file. Note that according to https://kripken.github.io/emscripten-site/docs/getting_started/FAQ.html#faq-when-safe-to-call-compiled-functions you should not try to run any Emscripten functions, until the C++ main function has run. To detect this, you can, for example, call your own Javascript function from main (there are other ways).
The fact this wasn't causing a problem before could have been something that seems quite unrelated: a change or update in the web browser, changing limits of concurrent downloads, or a change in the web server this is running from. You could look in the Network tab in the browser to see if anything leaps out at you as being different or suspicious.
However, as main isn't even reached, then it might not be that. I would try commenting out virtually all of your code, and make it so you have practically nothing but a hello-world program. Perhaps you don't have a correct setting in the Module object, or maybe the request for the memory initialization file is failing (you can check in the Network tab in the browser for that one). If your basic hello world program still isn't working, then you could post again, with its code, in a separate question.
This can also happens when the browser runs out of memory. Unfortunately, the browser's memory handling is not in our control so there isn't much you can do beside reducing your payload. This includes code size, preload content size, etc. Basically anything that can reduce the total memory consumption of your program will help fixing this. Browser vendors are constantly working to improve this, but it's going to take a while still.
I think you haven't given enough information to really know for sure. But it might be for instance that your js suddenly crossed some memory threshold which exceeds what the browser wants to allocate to it. You could try reducing the amount of memory used / streaming some assets instead of preloading them / ship less code / use -Os optimization level?
Lets take an example here which is known everywhere in the IT world:
We have a game, for example solitaire, and someone makes and releases a trainer for it that your moves are always '0'.
How do I programatically determine which adresses and what values that "hack" changes?
What way would be the best, if this is possible?
From within the game [injecting/loading my own dll?]
By intercepting traffic between the hack and target process with my own process?
I ask this question because of 2 things:
Protect an application from being "hacked" (at least by the script kiddies)
Reverse engineer a trainer (so you don't have to reinvent the wheel / avoid NIH syndrome)
You can't. Some broken attempts may be setting two addresses and then comparing them (they will find the other address though). Or they can simply remove your compare call.
They can alter any protection function that you use to "programatically determine" to always return false results. They can do anything to your executable, so there is no way.
Unless you hook the kernel functions that open your process to modify the memory. But that is also breakable and if I am not wrong you need to get your "protection kernel driver" digitally signed now.
There is another way in which you load a DLL in every running and newly spawned processes (which will probably alert antiviruses about your program being a virus), with that DLL you hook OpenProcess (and if there is another alternative to it, that too) functions in each process and check if its targeted at your program, and prevent it if so. Search about function hooking. I believe there was something called "MS Detour" or something for it.
And still, the game will not even be close to safe.
To sum up, no way is good to protect your game locally. If you are storing scores or something you should create a server program and client should report every move to server.
Even then, they can create a bot to automatically respond to server. Then the best you can do is somehow verify it is a human that is playing. (maybe captcha or comparing the solving speed with human avarage?)
I am trying to figure out a "Failed to resume in time" problem. In one of our testers devices (which is an iPhone 4S with the latest OS) it happens very frequently, whereas in my own device it doesn't seem to happen at all.
Anyway, I got a few crashlogs. I am unable to trace the root of the cause though. I understand that the issue might be
1.When a process is holding up the main thread for too long.
2.When there is a memory issue.
I don't think the memory is much of an issue since it seems to happen when the user leaves the main menu and comes back. Nothing much is happening in the main menu so it probably is a task that runs too long.
Here is an excerpt from the crash log:
Can somebody help me or guide me on who I can trace the cause of the issue? Is there anyway to turn off the watchdog timer(probably not huh?) Also, what does highlighted thread refer to?
I have already checked my applicationDidBecomeActive & applicationWillEnterForeground to make sure there is nothing going on there.
To my knowledge there are no synchronous calls being made at this point. Does Reachability use synchronous calls to check for internet? How can I check for that?
I am not making any large data transfers upon resume.
I notice that GameCenter automatically logs in or check for log in upon resuming your app. Is there anyway to prevent this? Could this possibly cause a time out issue?
I tried doing a time profile, but I am not able to understand how to use it to analyze. If you can provide a good resource for that, that would be amazing.
Thanks!!!
You're currently in "trying to find the issue mode". You should switch to "try to find out how much of an issue this really is" mode.
So go find another 4S (actually as many as you can) to rule out that it's a device-specific issue. If it happens on all 4S it should be easier to pinpoint. If not, have someone else look over it, discuss possible causes. The peer programming approach often helps when you're stuck in a dead-end situation.
If the issue is only on that one device, you might want to check if it's broken (or "jailbroken") or might simply need a hard reboot (hold power and home for 10+ seconds).
If it only happens on some devices but not all, try to find what they have in common. This could be language/locale, or dictation, practically any kind of setting the user might have changed. If necessary, write a logger that logs as many settings as possible to your (web) server so you can compare settings one-by-one and quickly discard those that aren't in synch.
If only very few devices are affected, you could also ignore the issue and hope that additional crash logs from users will reveal the key to the issue.
Finally, there's always the option to disable suspend on terminate and instead terminate the app when the home button is pressed (as it was pre iOS 4). Unless of course the app has to run in background.
I'm trying to read variables from memory. Variables, that doesn't belong to my own program. For instance, let's say I have this Adobe Shockwave (.dcr) application running in browser and I want to read different variables from it. How it's being done? Do I need to hook the process? But it's running under virtual machine, so I don't know how to do it.
This task is pretty much trivial in normal w32 applications (as it is mainly just
CBT-hooking / subclassing), but as I mentioned before, I've got no idea how it's being
done with flash / shockwave.
I'm using C++ (VS9) as my development-environment, in case you wish to know.
Any hints would be highly appreciated, so thank you in advance.
Best regards,
nhaa123
If you're trying to do it manually just for one or two experiments, it's easy.
Try a tool like Cheat engine which is like a free and quick and simple process peeker. Basically it scans the process's memory space for given key values. You can then filter those initial search hits later as well. You can also change those values you do find, live. The link above shows a quick example of using it to find a score or money value in a game, and editing it live as the game runs.
without having debug Binaries/DLLs of the Apps, your only chance is asking some hackers.
Normally you can connect to a process with a debugger, but without the debugging symbols of the binaries you don't see any variable names - just memory addresses.
Further the Flash/Shockwave code runs inside a sandbox inside the browser to prevent security holes by manipulated Flash code. So you don't have a real chance to get access to the running Flash code / to the plugin executing the Flash code - except you have a manipulated version of such a plugin.
So your task is quite hard to solve without using less legal methods. The next hard thing is the virtual machine - this could be solved by implementing your app as a client/server solution, where the "inspector" / watchdog runs as server inside the virtual machine and the client requesting the variable status/content running on your normal host. The communication could be done as simple socket connection.
If you have the chance to write your own Flash/Shockwave plugin, you maybe could be able to see contents of variables.
Sorry, that I cannot help you any further.
ciao,
3DH