C++ cheat engine (memory scanner)
cheat-and-gin
is a program that you can use to modify the memory of another process while it is running.
Such a program is popular for hacking games that are running locally, but I build one to get familiar
with the particularities of modifying a program’s memory under Window and Linux for learning purposes.
Here’s an example where we give ourselves 999
dirt blocks by using an old version
of the cheat engine (the 999 blocks could actually be placed!):
Now all you have to do is find 1
diamond to actually find 999
…
I don’t actually encourage cheating in Minecraft
. This is more of an
interesting real test for a cheat engine… Please don’t use this in
multiplayer.
Here’s an example where we modify the value of a string variable in a python
REPL interprer. We can do the same with integers, for example.
A description of how a cheat engine works (and what platform functions are used) is provided in
the CheatEngine
‘s README
.
I use premake4
for build configuration. You can find a download link on premake’s website.
To create a Visual Studio
solution, use:
premake4 vs2017
You can then build in the solution.
To create a GNU Makefile and compile, run:
premake4 gmake
cd build
make
There is a provided program named FakeGame
which shows some fake game parameters (health, mana, gold, …)
which change every time a newline is entered along with their associated addresses:
> ./FakeGame/bin/FakeGame
health(4): 100 - 0x7ffcb173c07c
mana(4): 100 - 0x7ffcb173c078
gold(1): - 0x7ffcb173c077
miles(2): 5 - 0x7ffcb173c074
rate(4): 0.1 - 0x7ffcb173c070
science(8): 0.1 - 0x7ffcb173c068
We can then start our cheat engine and specify the name of the process that we want to attack.
Note that we’re playing with another process’ memory, so we need extra rights. I am doing so by
running with sudo
here:
> sudo ./CheatEngine/bin/CheatEngine
Process name: FakeGame
We enter FakeGame
and we are then prompted to know the size of the variable that we want to modify:
What is the type of the searched value?
A) unsigned byte
B) character
C) 16-bit integer
D) 32-bit integer
E) 64-bit integer
F) float
G) double
H) string
Value type: D
Say that we want to modify the health
(4
bytes), we enter the choice of 32-bit integer
.
We are then asked for the current value of the target variable:
Value for 32-bit integer: 100
We enter the observed 100
. We are told that multiple addresses hold our value:
10 memory address(es) containing the value.
Keep searching? (y/n): y
We want to pin down our address, so we’ll update our game (newline
in our FakeGame
process)
and keep searching with the updated value. Let’s start by updating the game:
health(4): 99 - 0x7ffd647d71ac
mana(4): 98 - 0x7ffd647d71a8
gold(1): ! - 0x7ffd647d71a7
miles(2): 15 - 0x7ffd647d71a4
rate(4): 0.3 - 0x7ffd647d71a0
science(8): 0.103 - 0x7ffd647d7198
We can then enter the updated value (99
):
Value for 32-bit integer: 99
Set a new value:
What value should the new address(es) have?
Value for 32-bit integer: 424242
Value(s) modified.
Finally, we can admire the results of our cheat by updating the FakeGame
:
health(4): 424241 - 0x7ffd3d5b7c5c
mana(4): 96 - 0x7ffd3d5b7c58
(...)
./CheatEngine/tests/bin/Tests