Name similarity check, release 6.0.0

build.gradle

@@ -7,7 +7,7 @@ defaultTasks 'clean', 'shadowJar', 'build'
 
 allprojects {
     group = 'me.xneox'
-    version = '6.0-SNAPSHOT'
+    version = '6.0.0'
 
     sourceCompatibility = JavaVersion.VERSION_1_8
     targetCompatibility = JavaVersion.VERSION_1_8
@@ -41,6 +41,7 @@ subprojects {
         // Shaded dependencies.
         implementation 'com.maxmind.geoip2:geoip2:2.15.0'
         implementation 'org.apache.commons:commons-compress:1.20'
+        implementation 'org.apache.commons:commons-text:1.9'
         implementation 'com.google.guava:guava:30.1.1-jre'
         implementation 'com.github.simplix-softworks:SimplixStorage:3.2.2'
         implementation 'org.spongepowered:configurate-hocon:4.1.1'

bukkit/src/main/java/me/xneox/epicguard/bukkit/ChatUtils.java

@@ -16,6 +16,7 @@ public static void checkUnsupportedVersion(GuardLogger logger) {
             logger.error(" AND UNSUPPORTED VERSION OF MINECRAFT (1.8).");
             logger.error(" Please update to the latest server software.");
             logger.error(" No support will be provided for any issues.");
+            logger.error(" https://neox.gitbook.io/epicguard-wiki/faq#spigot-1-8");
             logger.error("*******************************************************");
         }
     }

core/src/main/java/me/xneox/epicguard/core/EpicGuard.java

@@ -105,9 +105,10 @@ private void checkOutdatedJava() {
         String javaVer = System.getProperty("java.version");
         if (javaVer.startsWith("1.8")) {
             logger().error("*******************************************************");
-            logger().error("YOU ARE RUNNING ON AN OUTDATED VERSION OF JAVA (" + javaVer + ")");
-            logger().error("Support for this version will be dropped soon, it is recommended to update to Java 16.");
-            logger().error("It that's not possible, update to at least Java 11.");
+            logger().error(" YOU ARE RUNNING ON AN OUTDATED VERSION OF JAVA (" + javaVer + ")");
+            logger().error(" Support for this version will be dropped soon, it is recommended to update to Java 16.");
+            logger().error(" It that's not possible, update to at least Java 11.");
+            logger().error(" https://neox.gitbook.io/epicguard-wiki/faq#java-8");
             logger().error("*******************************************************");
         }
     }

core/src/main/java/me/xneox/epicguard/core/check/impl/NameSimilarityCheck.java

@@ -0,0 +1,36 @@
+package me.xneox.epicguard.core.check.impl;
+
+import com.google.common.collect.EvictingQueue;
+import me.xneox.epicguard.core.EpicGuard;
+import me.xneox.epicguard.core.check.Check;
+import me.xneox.epicguard.core.user.PendingUser;
+import org.apache.commons.text.similarity.LevenshteinDistance;
+
+import javax.annotation.Nonnull;
+import java.util.List;
+import java.util.Queue;
+
+@SuppressWarnings("UnstableApiUsage")
+public class NameSimilarityCheck extends Check {
+    private final Queue<String> nameHistory = EvictingQueue.create(this.epicGuard.config().nameSimilarityCheck().historySize());
+    private final LevenshteinDistance distanceAlgorithm = LevenshteinDistance.getDefaultInstance();
+
+    public NameSimilarityCheck(EpicGuard epicGuard) {
+        super(epicGuard);
+    }
+
+    @Override
+    public boolean handle(@Nonnull PendingUser user) {
+        for (String nick : this.nameHistory) {
+            if (this.distanceAlgorithm.apply(nick, user.nickname()) <= this.epicGuard.config().nameSimilarityCheck().distance()) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    @Override
+    public @Nonnull List<String> kickMessage() {
+        return this.epicGuard.messages().disconnect().nameSimilarity();
+    }
+}

core/src/main/java/me/xneox/epicguard/core/config/MessagesConfiguration.java

@@ -179,6 +179,10 @@ public static final class Disconnect {
                 "&8» &7You have been kicked by &bAntiBot Protection&7:",
                 "&8» &cYou must add our server to your servers list to verify yourself.");
 
+        private final List<String> nameSimilarity = Arrays.asList(
+                "&8» &7You have been kicked by &bAntiBot Protection&7:",
+                "&8» &cYour nickname is too similar to other users connecting to the server.");
+
         private final List<String> settingsPacket = Arrays.asList(
                 "&8» &7You have been kicked by &bAntiBot Protection&7:",
                 "&8» &cBot-like behaviour detected, please join the server again.");
@@ -215,6 +219,10 @@ public List<String> serverListPing() {
             return this.serverListPing;
         }
 
+        public List<String> nameSimilarity() {
+            return this.nameSimilarity;
+        }
+
         public List<String> settingsPacket() {
             return this.settingsPacket;
         }

core/src/main/java/me/xneox/epicguard/core/config/PluginConfiguration.java

@@ -32,6 +32,8 @@ public class PluginConfiguration {
     private final AccountLimitCheck accountLimitCheck = new AccountLimitCheck();
     private final SettingsCheck settingsCheck = new SettingsCheck();
     private final NicknameCheck nicknameCheck = new NicknameCheck();
+    private final NameSimilarityCheck nameSimilarityCheck = new NameSimilarityCheck();
+
     private final ConsoleFilter consoleFilter = new ConsoleFilter();
     private final AutoWhitelist autoWhitelist = new AutoWhitelist();
     private final Misc misc = new Misc();
@@ -165,6 +167,39 @@ public String expression() {
         }
     }
 
+    @ConfigSerializable
+    public static final class NameSimilarityCheck {
+        @Comment("NameSimilarityCheck will detect similar nicknames\n"
+                + "of the connecting users.\n" +
+                "NEVER - check is disabled.\n" +
+                "ATTACK - check will be performed only during bot-attack.\n" +
+                "ALWAYS - check will be always performed.")
+        private final String checkMode = "ATTACK";
+
+        @Comment("How many nicknames should be keep in the history?\n" +
+                "When an user is connecting to the server, his nickname will be added to the history.\n" +
+                "Then the nickname will be compared with other nicknames stored in the history.\n" +
+                "(!) Requires restart to apply.")
+        private final int historySize = 10;
+
+        @Comment("The lower the distance, the similar the names.\n" +
+                "If the distance detected is lower or the same as\n" +
+                "configured below, it will be considered as a positive detection.")
+        private final int distance = 1;
+
+        public String checkMode() {
+            return this.checkMode;
+        }
+
+        public int historySize() {
+            return this.historySize;
+        }
+
+        public int distance() {
+            return this.distance;
+        }
+    }
+
     @ConfigSerializable
     public static final class ConsoleFilter {
         @Comment("Change when the console-filter should be active.\n" +
@@ -308,6 +343,10 @@ public NicknameCheck nicknameCheck() {
         return this.nicknameCheck;
     }
 
+    public NameSimilarityCheck nameSimilarityCheck() {
+        return this.nameSimilarityCheck;
+    }
+
     public ConsoleFilter consoleFilter() {
         return this.consoleFilter;
     }

core/src/main/java/me/xneox/epicguard/core/handler/DetectionHandler.java

@@ -45,6 +45,7 @@ public DetectionHandler(EpicGuard epicGuard) {
         checks.add(new ReconnectCheck(epicGuard));
         checks.add(new AccountLimitCheck(epicGuard));
         checks.add(new NicknameCheck(epicGuard));
+        checks.add(new NameSimilarityCheck(epicGuard));
         checks.add(new ProxyCheck(epicGuard));
     }