Prevent In-Login Player Teleportation

It's a curious bug that's been discovered, allowing players to teleport to other players while still in the login process. Normally, when you first spawn into a game, especially in certain server setups that use a login dimension or a spectator mode during authentication, you're in a sort of limbo. You're not fully in the game world yet, but you're also not entirely out. The unexpected behavior here is that even in this semi-logged-in state, players can access spectator menus and use number keys to initiate teleports to other players. This not only breaks the intended login flow but also creates a potential security vulnerability. By repeatedly teleporting, players can effectively leak the coordinates of other players on the server. This is especially problematic for servers that rely on mods, as the standard protections might not be equipped to handle this specific edge case during the authentication phase. The goal is to find a robust solution that patches this exploit, ensuring a smoother and more secure entry into the game for everyone. This means looking into how the spectator menu and teleportation mechanics are handled before a player is fully authenticated and present in the active game world. The implications of this bug are significant, as it bypasses intended game mechanics and can lead to unwanted information disclosure. Therefore, a fix needs to be comprehensive, addressing the root cause of why these actions are permissible during login.

Understanding the Login Dimension and Spectator Mode

When servers implement a login dimension or a similar system, the primary intention is to provide a safe and controlled environment for players to authenticate before joining the main game world. This often involves placing players in a spectator mode by default. This spectator mode is usually designed to prevent interaction with the game world, ensuring that players can't grief, move items, or interfere with ongoing gameplay while their login status is being processed. The idea is that you're an observer, waiting for the green light to enter the actual game. However, the bug we're discussing highlights a critical flaw in this setup. It appears that even within this spectator state, the number keys used to access the spectator menu are still active, and more importantly, the teleportation functionality within that menu remains functional. This is unexpected because typically, actions that involve interacting with or moving within the game world should be disabled until full authentication. The ability to teleport to other players, even in spectator mode, means that the spectator system isn't as isolated as it should be. It suggests that the game is still registering player positions and allowing for interaction commands to be processed, even if the player character isn't visually represented in the main world. The core issue lies in the disconnect between the player's authenticated state and the activation of certain game mechanics. If the teleportation feature, which is usually tied to admin or moderator tools, can be accessed by any player in this pre-login state, it implies that the security layer is being bypassed. This allows for the leak of player coordinates, as a malicious actor could repeatedly teleport to different players to gather their locations, potentially for later exploitation. The lack of specific fabric mods to counter this indicates it might be a more fundamental issue with how certain server plugins or vanilla game mechanics interact with the pre-login state.

The Mechanism of Coordinate Leaking

The coordinate leaking aspect of this bug is a significant concern for any server administrator or player who values privacy and security. When a player is in the login dimension and can access the spectator menu, they can select other players and initiate a teleport. While they might not be able to fully join the game and interact, the act of teleporting often reveals the coordinates of the target player. If a player repeatedly uses this functionality, they can effectively map out the locations of other players on the server. Imagine a scenario where a player wants to find a specific resource node, a hidden base, or simply locate other players for nefarious purposes. By exploiting this bug, they can achieve this without ever fully logging in. The process might involve looking at the spectator UI, which often displays coordinates, or the very act of attempting to teleport might trigger a log entry or an internal game state update that reveals the information. This bypasses intended game progression and security measures. Typically, discovering coordinates requires in-game exploration or specific tools. Allowing this during the login process undermines the entire integrity of player presence and discovery. For servers with competitive elements or valuable in-game assets, this could be devastating. Players could gain an unfair advantage by knowing where opponents are or where valuable resources are located before they've even properly entered the game. The fact that this is happening during the login process means it's happening before a player has even passed the initial gate. This suggests that the systems controlling access and abilities during authentication are not granular enough. They are either too permissive, allowing features that should be locked down, or the spectator mode itself is not properly isolated from the rest of the game's command processing. The absence of readily available fabric mods to fix this points to a potential need for a more fundamental adjustment in server configuration or a targeted mod developed specifically to address this pre-login interaction exploit. It's a vulnerability that requires careful consideration to prevent widespread abuse.

Why Standard Protections Might Fail

Many servers rely on a variety of fabric mods and plugins to enhance gameplay, enforce rules, and improve security. These often include anti-cheat systems, anti-griefing measures, and player management tools. However, the bug where players can teleport to other players while in the login process highlights a scenario that these standard protections might not be designed to address. The core reason is that most security measures are activated and enforced after a player has successfully authenticated and entered the main game world. They are built to monitor player actions within the active game environment, looking for suspicious behavior, unauthorized commands, or exploits that occur during normal gameplay. The login dimension, or the spectator state preceding full entry, is often treated as a separate, controlled environment. The assumption is that players in this state have limited capabilities, and thus, a lower level of monitoring is required. Standard anti-cheat systems might not even be active or fully functional in this pre-login spectator dimension. They might not have the necessary hooks or permissions to intercept actions like opening spectator menus or initiating teleports. Similarly, plugins designed to prevent teleportation abuse typically operate on the premise that players are already in the game and have access to their normal movement mechanics. They might not account for a player who is technically not yet in the game but can still issue commands that affect player positions. The vulnerability lies in the fact that the game is still processing player inputs and world states to some degree, even before full login. This allows commands that would normally be restricted to authenticated players with specific permissions (like admins using spectator commands) to be accessible. This makes the issue difficult to patch with generic mods. A solution needs to specifically target the pre-login phase, ensuring that teleportation and spectator menu access are completely disabled or severely restricted until the player's identity and connection are fully verified and they are admitted to the main game world. It’s a gap in the security architecture that clever exploits can exploit, especially if the server software or mods haven't been specifically coded to account for this transitional state.

The Need for a Specific Fix

Given the limitations of standard security plugins, it's clear that a specific fix for the in-login teleportation bug is necessary. Generic anti-cheat or anti-griefing mods are often designed to monitor actions within the game world after a player has fully joined. They might not have the capability to interfere with actions taken in a separate login dimension or during the initial authentication handshake. This means that if a server relies solely on these common mods, this particular exploit will likely remain open. The problem is that the game client might still be sending and processing certain commands, like opening menus or attempting teleports, even when the player isn't technically