How to Stop Your FiveM Server Being Hacked

If your FiveM server keeps getting hacked, duped or crashed no matter what anticheat you run, the problem almost certainly is not the anticheat. It is your scripts. This guide explains why, and exactly what to lock down.

Why your server keeps getting hacked

Most people picture a "hacker" as someone running a cheat menu. On FiveM, the more damaging attacks are not cheat menus at all: they are exploits of your own server-side scripts. An attacker sends a normal-looking event to your server and, because that event trusts them, they get money, items, admin powers, or they crash the whole thing.

These attacks look completely legitimate to an anticheat, because the player is not modifying their game, they are just talking to a script that was written to trust them.

An anticheat alone will not stop it

Anticheats detect cheating behaviour in the game and known cheat menus. They cannot read your resources or understand your logic. So a script that trusts client input or skips a permission check stays wide open even with a top-tier anticheat running. Run an anticheat, but understand it is one layer, not the whole solution.

1. Treat every server event as untrusted

This is the single biggest fix. Every RegisterServerEvent / server callback can be triggered by any player with the right name and arguments. So:

• Validate every argument. Never assume the client sent something sensible.
• Never trust a value the client sends, especially amounts, prices, item names or player IDs.
• Check permissions on the server. A client-side check means nothing to an exploiter.
• Rename default trigger names (the standard ESX/QBCore ones are public and targeted).

2. Lock down your economy (stop money and item dupes)

Money dupes happen when an event that adds money trusts a client-supplied amount, or can be spammed with no server check. To close this:

• Calculate every payout and price on the server, never from a value the client sent.
• Set sane transaction limits and reject anything over them.
• Log large or unusually frequent transactions so you can spot abuse.

3. Prevent server crashes

Crash exploits usually work by spamming an event or sending malformed data until the server buckles.

• Rate limit events per player, so one person cannot fire a trigger thousands of times a second.
• Validate input types and lengths before doing anything with them.
• Watch for entity and event spam, and drop players who exceed sane limits.

4. Stop unauthorised admin access

If admin actions are gated only on the client, or the admin event does not re-check who is calling it, a normal player can hand themselves admin. Every privileged action must confirm, on the server, that the caller actually has that permission.

5. Keep everything updated

Run the latest server artifacts from the official Cfx.re source, keep your resources updated, and follow the developers of the scripts you use for security fixes. Old versions of popular resources are where a lot of public exploits live.

6. Add a firewall and DDoS protection

Separate from in-game exploits, your host itself can be attacked. A properly configured firewall and DDoS protection blocks a lot of malicious traffic before it ever reaches your server.

Still getting hit? Get your scripts audited

The catch with all of the above is that the dangerous flaws are hidden inside your resources, and finding them means reading the code. That is exactly what a penetration test does: someone goes through your server, finds the exploitable scripts before an attacker does, and shows you how to patch each one.