diff --git a/extensions/guacamole-auth-ldap/src/main/java/org/apache/guacamole/auth/ldap/ObjectQueryService.java b/extensions/guacamole-auth-ldap/src/main/java/org/apache/guacamole/auth/ldap/ObjectQueryService.java
index 07e713c..e1fa2bb 100644
--- a/extensions/guacamole-auth-ldap/src/main/java/org/apache/guacamole/auth/ldap/ObjectQueryService.java
+++ b/extensions/guacamole-auth-ldap/src/main/java/org/apache/guacamole/auth/ldap/ObjectQueryService.java
@@ -37,6 +37,7 @@
 import org.apache.directory.api.ldap.model.filter.EqualityNode;
 import org.apache.directory.api.ldap.model.filter.ExprNode;
 import org.apache.directory.api.ldap.model.filter.OrNode;
+import org.apache.directory.api.ldap.model.filter.PresenceNode;
 import org.apache.directory.api.ldap.model.message.Referral;
 import org.apache.directory.api.ldap.model.message.SearchRequest;
 import org.apache.directory.api.ldap.model.name.Dn;
@@ -149,14 +150,25 @@
         // Include all attributes within OR clause
         OrNode attributeFilter = new OrNode();
 
-        // Add equality comparison for each possible attribute
-        attributes.forEach(attribute ->
-            attributeFilter.addNode(new EqualityNode(attribute, 
-                    (attributeValue != null ? attributeValue : "*")))
-        );
+        // If value is defined, check each attribute for that value.
+        if (attributeValue != null) {
+            attributes.forEach(attribute ->
+                attributeFilter.addNode(new EqualityNode(attribute,
+                        attributeValue))
+            );
+        }
+        
+        // If no value is defined, just check for presence of attribute.
+        else {
+            attributes.forEach(attribute ->
+                attributeFilter.addNode(new PresenceNode(attribute))
+            );            
+        }
 
         searchFilter.addNode(attributeFilter);
 
+        logger.trace("Sending LDAP filter: \"{}\"", searchFilter.toString());
+        
         return searchFilter;
 
     }