Authentic Eaglercraft hacks are usually .html files or JavaScript injections. If a link asks you to download an .exe or .msi file, it is likely a virus.
If you’re looking for security research or penetration testing resources for Minecraft/Eaglercraft (with proper authorization), I can point you toward general secure coding or vulnerability disclosure practices instead. Let me know how you’d like to proceed. Eaglercraft Hacked Client Links