diff --git a/plugins/ldap/lib/ldap_authentication.rb b/plugins/ldap/lib/ldap_authentication.rb
index 7171858..7fc2219 100644
--- a/plugins/ldap/lib/ldap_authentication.rb
+++ b/plugins/ldap/lib/ldap_authentication.rb
@@ -136,8 +136,16 @@ class LdapAuthentication
   def self.get_attr(entry, attr_name)
     if !attr_name.blank?
       val = entry[attr_name].is_a?(Array) ? entry[attr_name].first : entry[attr_name]
-      charset = Magic.guess_string_mime_encoding(val)
-      val.encode 'utf-8', charset, invalid: :replace, undef: :replace
+      if val.nil?
+        Rails.logger.warn "LDAP entry #{entry.dn} has no attr #{attr_name}."
+        nil
+      elsif val == '' || val == ' '
+        Rails.logger.warn "LDAP entry #{entry.dn} has attr #{attr_name} empty."
+        ''
+      else
+        charset = Magic.guess_string_mime_encoding(val)
+        val.encode 'utf-8', charset, invalid: :replace, undef: :replace
+      end
     end
   end
 
diff --git a/plugins/ldap/test/unit/ldap_authentication_test.rb b/plugins/ldap/test/unit/ldap_authentication_test.rb
index b57632a..f4b1e8f 100644
--- a/plugins/ldap/test/unit/ldap_authentication_test.rb
+++ b/plugins/ldap/test/unit/ldap_authentication_test.rb
@@ -3,6 +3,12 @@ require File.dirname(__FILE__) + '/../test_helper'
 
 class LdapAuthenticationTest < ActiveSupport::TestCase
 
+  def pseudoEntry(data)
+    entry = data.clone
+    def entry.dn; 'testDN'; end
+    entry
+  end
+
   def setup
     @ldap_config = load_ldap_config
   end
@@ -139,11 +145,35 @@ class LdapAuthenticationTest < ActiveSupport::TestCase
   end
 
   should 'detect and convert non utf-8 charset from ldap' do
-    entry = { 'name' => "Jos\xE9 Jo\xE3o" }
+    entry = pseudoEntry('name' => "Jos\xE9 Jo\xE3o")
     name = LdapAuthentication.get_attr entry, 'name'
     assert_equal name, 'José João'
   end
 
+  should 'dont crash when entry key is empty string' do
+    entry = pseudoEntry('name' => "")
+    name = LdapAuthentication.get_attr entry, 'name'
+    assert_equal name, ''
+  end
+
+  should 'dont crash when entry key has only a space char' do
+    entry = pseudoEntry('name' => " ")
+    name = LdapAuthentication.get_attr entry, 'name'
+    assert_equal name, ''
+  end
+
+  should 'dont crash when entry key is nil' do
+    entry = pseudoEntry('name' => nil)
+    name = LdapAuthentication.get_attr entry, 'name'
+    assert_equal name, nil
+  end
+
+  should 'dont crash when entry key does not exists' do
+    entry = pseudoEntry({})
+    name = LdapAuthentication.get_attr entry, 'name'
+    assert_equal name, nil
+  end
+
   if ldap_configured?
     should 'return the user attributes' do
       auth = LdapAuthentication.new(@ldap_config['server'])
--
libgit2 0.21.2