Marvel's Avengers Server Emulator

Client and Server emulator for Marvel's Avengers. The client is responsible to downgrade the connection encryption enforcement and redirecting it to the localhost(127.0.0.1). The server responds with pre-recorded JSON from Square Enix Servers, they're tied to my game progress at the moment.

You can read the blogpost about this project at: https://krystalgamer.github.io/avengers-emulator/

Video of the emulator in action: https://www.youtube.com/watch?v=MLn475soq1M

Installation

Client

Download the latest release. Rename the original osdk.dll to osdk_orig.dll and drop the one from the release.

When the game starts you should now have a console which logs curl_easy_setopt calls and hooks/patches.

Server

Install Python 3.

Go the server folder and run python -m pip install -r requirements.txt. It only needs to be ran once per python installation.

Run the server with python server.py.

Notes

If python does not work try python3.

Currently the server listens on localhost so it must be on ther same server as the client.

If you already have python installation and don't want to polute the package namespace, you can create a virtual environment. This tutorial covers it in-depth.

Client

Forwards all DLL calls to the original osdk_orig.dll.

Hooks(IAT) getaddrinfo forcing it to return localhost information.

Hooks(trampoline) curl_easy_setopt to control the network flow.

Drops the encryption enforcement by injecting CURLOPT_SSL_VERIFYHOST and CURLOPT_SSL_VERIFYPEER.

Dumping capabilities are disabled - uncomment and fix the paths to re-enable them.

Server

Flask server with adhoc ssl_context, which allows for on the fly certificate generation.

Answers with JSONs from jsons folder.

Defined most critical endpoints to allow gameplay.

405 handler exists due to the client prefixing the HTTP method with a token.

merge_slashes is disabled to the client having double-slashes URL and Flask not liking it.

TODO

• [ ] Have an actual Database
• [ ] Fix the market
• [ ] Improve the 405 handler
• [ ] Custom server address configuration