What Is AntiCommandTab and Why Your Server Needs It
Every server administrator knows the uneasy feeling of seeing a new player join and immediately start typing suspicious commands. Often, these are not harmless curiosity but deliberate attempts to map out your server's plugins, versions, and potential weaknesses. AntiCommandTab is a lightweight yet powerful security plugin designed to shut down these reconnaissance efforts before they even begin. It specifically guards against Layer 1 CoPY-Cat attacks, where an attacker tries to discover what plugins you run by using the tab-completion feature or common informational commands. With AntiCommandTab, you can keep your server's inner workings private and maintain a secure, unpredictable environment.
How Layer 1 CoPY-Cat Attacks Work
In the Minecraft server ecosystem, a CoPY-Cat attack refers to a method where a malicious user attempts to copy your server's setup by probing for plugin names. The attacker relies on the fact that many plugins expose themselves through commands like /pl, /plugins, /version, or /ver. Even more subtle, they can use the [TAB] key to autocomplete partial commands, revealing valid plugin commands and their aliases. Once they know what plugins you have, they can search for known exploits, outdated versions, or configuration flaws. AntiCommandTab blocks all these avenues at the very first layer, stopping the information leak instantly.
Core Features of AntiCommandTab
AntiCommandTab is deceptively simple but covers every common probe vector. Its feature set is focused entirely on prevention:
- Blocks /[TAB] – Disables tab-completion for all commands that might reveal plugin names, making it impossible to list commands by cycling through suggestions.
- Blocks /ver [TAB] – Prevents tab-completion specifically for version-related commands, so attackers cannot autocomplete to see if
/veror/versionexists. - Blocks /version [TAB] – Stops tab-completion for the
/versioncommand, a common way to check server software and plugin versions. - Blocks /about [TAB] – Disables tab-completion for
/about, another command that often reveals server and plugin details. - Blocks /pl and /plugins – Completely hides the output of the plugin listing commands, even if typed manually without tab-completion.
- Blocks /about – Suppresses the
/aboutcommand output entirely. - Blocks /version and /ver – Prevents the version commands from displaying any information.
- Blocks /? – Stops the help command that could list available commands.
All these blocks work silently, returning a customizable deny message instead of the actual command output. This way, the attacker sees nothing useful and may even think the commands simply don't exist.
Installation and Requirements
Getting AntiCommandTab running on your server is straightforward. The only hard requirement is ProtocolLib, a widely used library that allows plugins to interact with the Minecraft protocol at a low level. ProtocolLib must be installed and enabled before you drop AntiCommandTab into your plugins folder. Once both are in place, restart your server and the protection activates immediately with sensible defaults. For those who manage multiple mods and want a streamlined experience, this plugin can be easily installed via the foxygame.net launcher — a convenient, flexible, and modern Minecraft launcher where you can download mods right from the menu without digging through countless web pages. The launcher handles dependencies like ProtocolLib automatically, making setup almost effortless.
Configuration and Customization
AntiCommandTab comes with a clean config.yml file that lets you tailor the deny message to your liking. You can use full chat formatting codes, including color and style, so the message blends perfectly with your server's theme or acts as a deterrent. For example, you might set a friendly message like "That command is not available here" or a more stern "Access denied." The plugin blocks all the commands by default, but you can adjust which ones are blocked if you only need partial protection. The configuration is well-documented, and changes take effect after a server reload or restart.
Permissions and Bypass
While you want to block outsiders, your staff and trusted players still need to use these commands for legitimate administration. AntiCommandTab includes a bypass permission: lib.commandtab.bypass. Any player or group with this permission will be able to use tab-completion and see the output of blocked commands as normal. This allows you to grant full visibility to moderators and admins while keeping everyone else in the dark. Permission management is done through your usual permissions plugin like LuckPerms, so you can integrate it seamlessly into your existing rank system.
Why Simple Blocking Matters
Some server owners underestimate how much information leaks through basic commands. A simple /version tells an attacker your server software (Spigot, Paper, etc.) and its exact build, which can be cross-referenced with known vulnerabilities. The /plugins list is a goldmine for anyone looking to exploit outdated or misconfigured plugins. By blocking these at the command level, AntiCommandTab removes the easiest reconnaissance path. Combined with other security measures like a firewall and regular updates, it creates a robust first line of defense that requires no ongoing maintenance.
Conclusion
AntiCommandTab is a must-have for any public Minecraft server that values privacy and security. It plugs the most obvious information leaks without affecting legitimate gameplay or administration, thanks to its bypass permission. The setup is minimal, the performance impact is negligible, and the peace of mind is invaluable. Whether you run a small community server or a large network, stopping CoPY-Cat attacks at the source keeps your plugins and versions hidden from prying eyes. Install it today and take control of what your server reveals to the world.