Added some Checks, yeah thats it :)

src/main/java/de/febanhd/anticrash/AntiCrash.java

@@ -59,6 +59,8 @@ private void registerChecks() {
         this.checks.add(new DosCheck());
         this.checks.add(new SignCheck());
         this.checks.add(new EnderPortalCheck());
+        this.checks.add(new Log4JExploitCheck());
+        this.checks.add(new ChatMessageCheck());
 
     }
 

src/main/java/de/febanhd/anticrash/checks/AbstractCheck.java

@@ -91,6 +91,20 @@ public void sendInvalidPacketWarning(Player player, PacketEvent event, String re
         });
     }
 
+    public void sendInvalidPacketWarning(Player player, String reason) {
+        if(lastReasonsMap.containsKey(player) && lastReasonsMap.get(player).equals(reason)) return;
+        lastReasonsMap.put(player, reason);
+
+        String playerName = this.getPlayerName(player);
+
+        Bukkit.getScheduler().scheduleSyncDelayedTask(this.getPlugin(), () -> {
+            new Broadcast("anticrash.notify", players -> {
+                players.sendMessage(AntiCrash.PREFIX + "§c" + playerName + " §7tryed to crash the server!");
+                players.sendMessage(AntiCrash.PREFIX + "§cReason: §7" + reason);
+            });
+        });
+    }
+
     public void sendCrashWarning(Player player, String reason) {
         this.closeChannel(player);
         if(lastReasonsMap.containsKey(player) && lastReasonsMap.get(player).equals(reason)) return;

src/main/java/de/febanhd/anticrash/checks/impl/ChatMessageCheck.java

@@ -0,0 +1,72 @@
+package de.febanhd.anticrash.checks.impl;
+
+import com.comphenix.protocol.PacketType;
+import com.comphenix.protocol.events.PacketEvent;
+import de.febanhd.anticrash.checks.AbstractCheck;
+import de.febanhd.anticrash.plugin.AntiCrashPlugin;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.Listener;
+import org.bukkit.event.player.AsyncPlayerChatEvent;
+import org.bukkit.event.player.PlayerCommandPreprocessEvent;
+
+import java.util.concurrent.ConcurrentHashMap;
+
+public class ChatMessageCheck extends AbstractCheck implements Listener {
+
+    private ConcurrentHashMap<Player, Long> lastMessage;
+
+    public ChatMessageCheck() {
+        super("Chat Message Check");
+        lastMessage = new ConcurrentHashMap<>();
+        Bukkit.getPluginManager().registerEvents(this, AntiCrashPlugin.getPlugin());
+    }
+
+    @EventHandler
+    public void handleChat(AsyncPlayerChatEvent event){
+        if(lastMessage.containsKey(event.getPlayer())){
+            if(System.currentTimeMillis() - lastMessage.get(event.getPlayer()) < 100){
+                this.sendInvalidPacketWarning(event.getPlayer(), "Sent messages too fast (<100ms)");
+                event.setCancelled(true);
+            }
+            lastMessage.replace(event.getPlayer(), System.currentTimeMillis());
+        }else lastMessage.put(event.getPlayer(), System.currentTimeMillis());
+    }
+
+    @EventHandler
+    public void handlePreCommand(PlayerCommandPreprocessEvent event){
+        if(event.getMessage().contains("/calc") || event.getMessage().contains("/solve") || event.getMessage().contains("/eval") || event.getMessage().contains("/desc")){
+            if(event.getMessage().contains("(")
+                    || event.getMessage().contains(")")
+                    || event.getMessage().contains("[")
+                    || event.getMessage().contains("]")
+                    || event.getMessage().contains("{")
+                    || event.getMessage().contains("}")
+                    || event.getMessage().contains("?")
+                    || event.getMessage().contains(":")
+                    || event.getMessage().contains(";")){
+                this.sendInvalidPacketWarning(event.getPlayer(), "The player executed a dangerous WorldEdit Crash Command. (Calculation)");
+                event.setCancelled(true);
+            }else if(event.getMessage().length() > 20){
+                this.sendInvalidPacketWarning(event.getPlayer(), "The player executed a dangerous WorldEdit Crash Command. (Calculation)");
+                event.setCancelled(true);
+            }
+        }
+
+        if(event.getMessage().contains("mv") && (event.getMessage().contains("\n") || event.getMessage().contains(".*.*")) || event.getMessage().contains(String.valueOf((char) 775))){
+            this.sendInvalidPacketWarning(event.getPlayer(), "The player executed a Crash Command. (MV Crasher / Bad Char)");
+            event.setCancelled(true);
+        }
+
+        if(event.getMessage().contains("mv") && (event.getMessage().contains("/") || event.getMessage().contains("\\"))){
+            this.sendInvalidPacketWarning(event.getPlayer(), "The player executed a dangerous Multiverse Command. (Path Navigation)");
+            event.setCancelled(true);
+        }
+
+        if((event.getMessage().contains("pex promote a a") || event.getMessage().contains("pex demote a a")) && event.getMessage().startsWith("/")){
+            this.sendInvalidPacketWarning(event.getPlayer(), "The player executed a permission ex crash command. (Promote/Demote)");
+            event.setCancelled(true);
+        }
+    }
+}

src/main/java/de/febanhd/anticrash/checks/impl/Log4JExploitCheck.java

@@ -0,0 +1,78 @@
+package de.febanhd.anticrash.checks.impl;
+
+import de.febanhd.anticrash.checks.AbstractCheck;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.core.Appender;
+import org.apache.logging.log4j.core.LogEvent;
+import org.apache.logging.log4j.core.filter.AbstractFilter;
+import org.apache.logging.log4j.core.filter.AbstractFilterable;
+import org.bukkit.Bukkit;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.Listener;
+import org.bukkit.event.player.AsyncPlayerChatEvent;
+import org.bukkit.event.player.PlayerCommandPreprocessEvent;
+import java.util.List;
+import java.util.Map;
+import java.util.logging.Logger;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+
+public class Log4JExploitCheck extends AbstractCheck {
+
+    private static final Pattern PATTERN = Pattern.compile(".*\\$\\{[^}]*\\}.*");
+
+    public Log4JExploitCheck() {
+        super("Log4J Exploit Check");
+        Logger logger = plugin.getLogger();
+
+        plugin.getServer().getPluginManager().registerEvents(new Listener() {
+
+            @EventHandler
+            public void handleMessage(AsyncPlayerChatEvent chatEvent){
+                if(chatEvent.getMessage().toLowerCase().contains("${jndi:ldap") || chatEvent.getMessage().toLowerCase().contains("${jndi")
+                        || chatEvent.getMessage().toLowerCase().contains("ldap")){
+                    sendInvalidPacketWarning(chatEvent.getPlayer(), "Tryed to exploit Log4J via chat");
+                    chatEvent.setCancelled(true);
+                }
+            }
+
+            @EventHandler
+            public void handleCommand(PlayerCommandPreprocessEvent event){
+                if(event.getMessage().toLowerCase().contains("${jndi:ldap") || event.getMessage().toLowerCase().contains("${jndi")
+                        || event.getMessage().toLowerCase().contains("ldap")){
+                    sendInvalidPacketWarning(event.getPlayer(), "Tryed to exploit Log4J via command");
+                    event.setCancelled(true);
+                }
+            }
+        }, plugin);
+
+        try {
+            this.applyAppenders();
+            logger.info("Successfully applied filters to all Appenders! (Log4J Fix)");
+        } catch (Exception exception) {
+            logger.warning("Failed to add Log4J Appenders (LoggerFilter) to Logger. (Incompatible Logger version)!");
+        }
+    }
+
+    private void applyAppenders() {
+        Map appenders = ((org.apache.logging.log4j.core.Logger)(LogManager.getRootLogger())).getAppenders();
+        LoggerFilter filter = new LoggerFilter();
+        List<Appender> filterable = (List<Appender>) appenders.values().stream().filter(appender -> appender instanceof AbstractFilterable).collect(Collectors.toList());
+        filterable.forEach(appender -> ((AbstractFilterable)(appender)).addFilter(filter));
+    }
+
+    private static class LoggerFilter
+            extends AbstractFilter {
+        private LoggerFilter() {
+        }
+
+        public Result filter(LogEvent event) {
+            String message = event.getMessage().getFormattedMessage();
+            if (message.indexOf(36) != -1 && PATTERN.matcher(message.toLowerCase()).find()) {
+                Bukkit.getConsoleSender().sendMessage("Server blocked Log4J Exploit try succesfully via Log Filter.");
+                return Result.DENY;
+            }
+            return super.filter(event);
+        }
+    }
+}

src/main/java/de/febanhd/anticrash/checks/impl/nbt/NBTTagCheck.java

@@ -8,6 +8,7 @@
 import com.google.common.collect.Lists;
 import de.febanhd.anticrash.checks.AbstractCheck;
 import de.febanhd.anticrash.checks.CheckResult;
+import org.bukkit.GameMode;
 import org.bukkit.Material;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
@@ -28,6 +29,13 @@ public NBTTagCheck() {
     @Override
     public void onPacketReceiving(PacketEvent event) {
         Player player = event.getPlayer();
+
+        if(event.getPacket().getType().equals(PacketType.Play.Client.SET_CREATIVE_SLOT)
+        && player.getGameMode() != GameMode.CREATIVE){
+            this.sendInvalidPacketWarning(player, event, "Sent creative slot packet without being in creative mode");
+            event.setCancelled(true);
+        }
+
         PacketContainer packet = event.getPacket();
         ItemStack stack = packet.getItemModifier().readSafely(0);
         if(stack == null) return;

src/main/java/de/febanhd/anticrash/commands/AntiCrashCommand.java

@@ -1,5 +1,6 @@
 package de.febanhd.anticrash.commands;
 
+import com.comphenix.protocol.PacketType;
 import de.febanhd.anticrash.AntiCrash;
 import de.febanhd.anticrash.checks.impl.nbt.NBTTagCheck;
 import de.febanhd.anticrash.plugin.AntiCrashPlugin;
@@ -12,9 +13,11 @@ public class AntiCrashCommand implements CommandExecutor {
 
     @Override
     public boolean onCommand(CommandSender sender, Command command, String s, String[] strings) {
-        if(sender instanceof Player) ((Player) sender).sendTitle("§4§lFAC", "§c§lMade by FebanHD <3");
 
-        sender.sendMessage(AntiCrash.PREFIX + "§cFixedFAC by §eFebanHD §7fixed by §eytendx §8| AntiCrash & AntiDos");
+        Player player =  ((Player) sender);
+        player.sendTitle("§4§lFAC", "§c§lMade by FebanHD <3");
+
+        sender.sendMessage(AntiCrash.PREFIX + "§cFixedFAC §7by §eFebanHD §7fixed by §eytendx §8| §7AntiCrash & AntiDoS");
         sender.sendMessage(AntiCrash.PREFIX + "§cVersion: §7" + AntiCrashPlugin.getPlugin().getDescription().getVersion());
         sender.sendMessage(AntiCrash.PREFIX + "§cChecks: §7" + AntiCrash.getInstance().getChecks().size());
         sender.sendMessage(AntiCrash.PREFIX + "§cNBTChecks: §7" + ((NBTTagCheck)AntiCrash.getInstance().getCheck(NBTTagCheck.class)).getChecks().size());

target/classes/plugin.yml

@@ -1,5 +1,5 @@
 name: FAC
-version: 1.2.9
+version: 1.2.9-FIXED
 main: de.febanhd.anticrash.plugin.AntiCrashPlugin
 author: FebanHD
 softdepend:

target/maven-archiver/pom.properties

@@ -1,5 +1,5 @@
 #Generated by Maven
-#Sun Jan 23 14:06:09 CET 2022
+#Sun Jan 23 14:59:02 CET 2022
 groupId=de.febanhd
 artifactId=FAC
-version=1.2.9
+version=1.2.9-FIXED