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Took a quick look, didn’t dive too deep yet. Already managed to expose part of the check (PBKDF2 → AES → "UNPACKED"), so it’s not as opaque as it first looks. This kind of protection layer is also something I’ve been dealing with in my own work: https://forum.tuts4you.com/topic/46002-continuation-fork-krypton-net-reactor-devirtualizer/#comment-229109 No full unpack yet, just a quick peek for now.

.NET Reactor v7.5.9.1 (Aggressive Settings + Custom Anti-Tamper) Hey everyone, I put together a small challenge for anyone interested in reversing .NET protections. This one is packed using .NET Reactor v7.5.9.1 with some pretty aggressive settings, along with a bit of custom anti-tamper logic on top. Your goal is to unpack the application and recover a clean, working assembly. Protections Enabled NecroBit String Encryption Obfuscation Anti ILDASM Hide Method Calls Code Virtualization Anti Tampering Anti Debug Merge Enums Control Flow Obfuscation (Level 9) Additional Protections Custom runtime anti-debug Anti-injection checks Integrity verification A background watchdog thread 🎯 Objectives 1. Primary: Unpack the application and produce a clean assembly that runs without errors 2. Bonus: Recover the correct password (completely optional) File Information Submitter Visual Studio Submitted 04/13/2026 Category UnPackMe (.NET) View File

7.5.9.1 NOT EXIST. https://www.eziriz.com/reactor_history.htm

Okey, it would be nice to share more similar challenges, this one was really interesting.

What do you mean? Can you show some screenshot how do you add custom anti-tamper? The difference I can see is: The anti-tamper method is called by EntryPoint in your target, but it's called by <Module>::.cctor in standard .NET Reactor.

If its not on the build you're using, I am assuming its coming in the near future.

@Visual Studio How do you add custom anti-tamper? Can we add custom anti-tamper on .net reactor 7.5?

Well done :) I can create some more challenges for you if you'd like, I also have Intellilock

Does .NET Reactor 7.5.9.1 exist in the world? Seems the latest is 7.5 : https://www.eziriz.com/reactor_download.htm