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Client Generator

Client Generator

Generates platform-specific agent executables from the SimpleServer JAR.

Capabilities

  • Target Platform: Windows (.exe), Linux (self-extracting binary), macOS (.app.zip)
  • App Info: Set agent name, version, company, description (embedded in Windows PE metadata)
  • Server Connection: Set controller Host/IP and Port — injected into the agent at build time
  • Source JAR: The SimpleServer fat JAR as the base
  • Icon: Optional custom icon (.ico for Windows, .icns for macOS)
  • Output Folder: Choose where generated files are saved
  • Build Log: Real-time log of each generation step
  • Progress bar: Visual generation progress

How Each Platform is Generated

Uses Launch4j (auto-downloaded from SourceForge) to wrap the JAR into a native Windows executable:

  • Full PE metadata: file version, product version, description, company, copyright
  • Embeds a custom icon
  • Minimum JRE version enforcement (Java 11+)
  • Silent GUI mode (no console window)

Creates a self-extracting shell script:

  • The agent JAR is Base64-encoded and embedded inside the script
  • On execution, decodes the JAR to a temp file and launches it with nohup java -jar
  • No build tools needed on the target — only java and base64
  • Sets executable bit automatically

Creates a proper macOS application bundle:

  • Contents/MacOS/ — launcher shell script
  • Contents/Java/ — the agent JAR
  • Contents/Info.plist — bundle metadata (name, version, bundle ID, icon)
  • Contents/Resources/ — optional .icns icon
  • Zipped into .app.zip for transfer

Config Injection

The controller IP and port are not hardcoded in the agent source. At generation time, the Client Generator:

  1. Opens the SimpleServer JAR as a ZIP
  2. Removes any existing aon.properties
  3. Writes a new aon.properties with host= and port=
  4. Repackages the JAR

The agent reads these values at startup to know where to connect.

What You Learn

Industry Comparison

This is exactly how msfvenom (Metasploit payload generator), Cobalt Strike's artifact kit, and enterprise MDM agent deployment tools work — taking a base agent, injecting environment-specific configuration (server address, port, certificates), and packaging it for each target platform. Launch4j is the same tool used by many legitimate Java applications to produce Windows executables.