diff --git a/src/main/scala/util/LDAPUtil.scala b/src/main/scala/util/LDAPUtil.scala
index 05a7171..cf6ffe7 100644
--- a/src/main/scala/util/LDAPUtil.scala
+++ b/src/main/scala/util/LDAPUtil.scala
@@ -49,7 +49,7 @@
     ){ conn =>
       findMailAddress(conn, userDN, ldapSettings.mailAttribute) match {
         case Some(mailAddress) => Right(LDAPUserInfo(
-          userName    = userName,
+          userName    = getUserNameFromMailAddress(userName),
           fullName    = ldapSettings.fullNameAttribute.flatMap { fullNameAttribute =>
             findFullName(conn, userDN, fullNameAttribute)
           }.getOrElse(userName),
@@ -59,6 +59,13 @@
     }
   }
 
+  private def getUserNameFromMailAddress(userName: String): String = {
+    (userName.indexOf('@') match {
+      case i if i < 0 => userName.substring(0, i)
+      case i          => userName
+    }).replaceAll("[^a-zA-Z0-9\\-_.]", "").replaceAll("^[_\\-]", "")
+  }
+
   private def bind[A](host: String, port: Int, dn: String, password: String, tls: Boolean, keystore: String, error: String)
                   (f: LDAPConnection => Either[String, A]): Either[String, A] = {
     if (tls) {