SLING-5483 : Unauthenticated request: getUserPrincipal() doesn't return null for auth.annonymous=true
diff --git a/src/main/java/org/apache/sling/auth/core/impl/SlingAuthenticator.java b/src/main/java/org/apache/sling/auth/core/impl/SlingAuthenticator.java
index c2e876a..6e203cc 100644
--- a/src/main/java/org/apache/sling/auth/core/impl/SlingAuthenticator.java
+++ b/src/main/java/org/apache/sling/auth/core/impl/SlingAuthenticator.java
@@ -1287,8 +1287,10 @@
             final HttpServletRequest request) {
 
         // HttpService API required attributes
-        request.setAttribute(ServletContextHelper.REMOTE_USER, resolver.getUserID());
         request.setAttribute(ServletContextHelper.AUTHENTICATION_TYPE, authType);
+        if ( authType != null ) {
+            request.setAttribute(ServletContextHelper.REMOTE_USER, resolver.getUserID());
+        }
 
         // resource resolver for down-stream use
         request.setAttribute(REQUEST_ATTRIBUTE_RESOLVER, resolver);