Mirror Networking's GUARD is anti-cheat solution designed specifically for multiplayer games regardless of game engine. In their words—it's a complete reimagining of how anti-cheat technology should work in modern gaming environments.

What is Anti-Cheat Software?

Anti-cheat software serves as a critical security layer that protects multiplayer games from players attempting to gain unfair advantages through cheating tools, modified game files, or unauthorized software. Traditional solutions run as separate processes alongside games, monitoring for suspicious behavior and blocking potential threats in real-time. These systems typically announce their presence and aggressively block suspected cheaters with obvious detection messages.

However, modern anti-cheat technology is evolving beyond these conventional approaches. The most effective solutions now focus on silent detection methods that maintain the element of surprise, preventing cheaters from adapting their tactics once they realize they've been caught.

What is Mirror Networking's GUARD?

GUARD represents a complete reimagining of anti-cheat technology, developed specifically for Unity multiplayer games after months of intensive research and development. Unlike conventional anti-cheat downloads that run as separate processes, GUARD embeds directly into your game's source code at the C# level, making it virtually invisible to potential cheaters. The system operates on a revolutionary "silent detection" philosophy—instead of blocking cheaters with obvious messages, it quietly reports suspicious activity to your game server.

This approach maintains a crucial information advantage since cheaters believe they were reported by other players rather than caught by automated systems. GUARD currently detects mod loaders like MelonLoader, DLL injection, instruction patching, debuggers, and virtual machines, with each detection accompanied by confidence ratings and detailed evidence for informed decision-making.

Is This an Easy Anti-Cheat to Integrate in My Game?

GUARD offers remarkably simple integration, particularly for Mirror Networking users who can implement it with just three clicks. The system requires minimal setup since it compiles directly with your project through Unity's IL2CPP compiler, eliminating the need for complex external configurations. Unlike traditional anti-cheat solutions that require extensive server-side infrastructure, GUARD sends reports directly to your existing game server.

The solution operates with zero risk to legitimate players since it runs in read-only, user-mode within a worker thread. This design ensures no performance impact, crashes, or false positives that could harm the gaming experience. For larger studios requiring additional security measures, source code access and custom obfuscation options are available at no extra charge.

Is This Anti-Cheat Software Built for Unity? What Versions Are Compatible?

GUARD was specifically designed and built for Unity games, taking advantage of Unity-specific features and compilation processes. The system works with Unity versions 2020 and above, including Unity 6, supporting all platforms where Unity's IL2CPP compiler operates, though current detection capabilities focus on Windows with mobile, Mac, and WebGL support planned for future releases. GUARD integrates at the source code level using Unity's IL2CPP compiler, which embeds the anti-cheat functionality directly into your game's final assembly.

The solution is completely netcode agnostic, meaning it works with any multiplayer Unity game regardless of your networking solution. While specific integrations are available for Mirror Networking, the system functions effectively with other networking frameworks as well. However, GUARD requires IL2CPP builds rather than Mono builds to maintain its stealth characteristics and prevent obvious detection.

Can I Download Mirror's GUARD Anti-Cheat? Where Can I Download It?

GUARD is currently available for Unity developers through Mirror Networking's distribution channels. The solution ships as an obfuscated DLL by default to prevent reverse engineering, though serious studios can request full source code access for additional security measures. Unlike subscription-based anti-cheat software, GUARD operates without cloud components, CCU tracking, or ongoing fees.

The system maintains a privacy-first approach by only scanning the game's own process and folder without accessing other parts of players' computers or phoning home to external servers. All detection reports go directly to your own game server, giving you complete control over the data and decision-making process. For support and bug reports, developers can access the GitHub repository at https://github.com/MirrorNetworking/Guard.

FAQ

As posted by vis2k, Mirror Networking's creator, on Discord on 2025.05.28

• Question: Does Guard protect against 100% of cheats?

  • No, and it never will. The goal is to reduce cheats to an acceptable minimum, while being as non-invasive as possible.

• Question: Can Guard be circumvented by cheaters?

  • Yep. Please don't tell your players that you are using anti-cheat, so no one will attempt to circumvent it. For example, blocking any cheating attempts with a "CHEAT DETECTED" popup would be a sure way to have your anti cheat circumvented.

• Question: Does Guard have subscription/CCU/Cloud pricing?

  • No, it never phones home and has no special restrictions. It's really just obfuscated C# code, no license management / DRM / nothing.

• Question: Does Guard scan player's computers?

  • Guard only ever reads from the game's own process, as well as the game folder.

  • We don't want this to be a security/privacy nightmare.

• Question: Can I trust the obfuscated DLL?

  • Yes, we still have to comply with the Asset Store guidelines, and we wouldn't risk the trust that we've built from a decade of open-source work on Mirror.

  • Large studios can totally get source code access and apply obfuscation by themselves for no extra charge - we really just want to keep the source away from cheaters.

• Question: Where can I report bugs?

  • On GitHub: https://github.com/MirrorNetworking/Guard/issues

• Question: Which successful games are using Guard in production?

  • With Guard aiming to remain stealthy/silent, studios don't really want to broadcast their usage of it. As of May 2025, it's used in a successful production game built with Mirror, detecting cheaters every single day.

• Question: How to debug issues when the stack trace is obfuscated?

  • Just post them on Github, we are able to de-obfuscate them.

• Question: How does this compare to Easy Anti Cheat, Valve Anti Cheat, other Assets, etc.?

  • Working on Mirror, I never tried any other netcodes. Working on Guard, I never tried any other anti cheats. The goal is to approach this from scratch with a fresh mind, we don't want to know what others do. We don't want to compete either, this is built for the studios that wanted it.

• Question: Can I auto-ban all cheat reports?

  • No. Reports always come with a 'Confidence {High, Medium, Low}' flag.

  • You could auto ban 'High' but should still add a random delay of a few hours or days - as if other players reported that user. Where as 'Medium' and 'Low' require human review. For example: random tools like Discord/Steam/Streaming are constantly injecting stuff into games, which may turn up in Guard's reports. Even for obvious cheat kits like Melon Loader, some people use this for legitimate mods. This is why Guard reports contain detailed evidence (i.e. which plugin was injected from Melon loader).

• Question: The Guard component itself isn't obfuscated, is this risky?

  • Kind of. It's really just a light wrapper to add Guard to Unity.

  • But you could totally rename this to something random so it's not as obvious to reverse engineers!

• Question: Does Guard support Mono builds?

  • Please DO NOT use Guard in mono builds, always enable IL2CPP.

  • While it technically works in mono builds, GuardSystem.dll would sit very obviously in your game's build folder, which we absolutely don't want people to see.

• Question: Does Guard work with Unity 6?

  • Works with all Unity versions > 2020.