--- a/OrthancExplorer/explorer.html	Thu Oct 03 13:44:08 2019 +0200
+++ b/OrthancExplorer/explorer.html	Fri Oct 04 17:41:43 2019 +0200
@@ -646,6 +646,19 @@
 
   <div id="dialog" style="display:none">
   </div>
+
+  <div id="template-insecure" style="display:none">
+    <div class="warning-insecure ui-body ui-body-e">
+      <h1>Insecure setup</h1>
+      <p>
+        Your Orthanc server is accepting remote connections, but is
+	using the default username and password. Please carefully read
+	your logs and review your configuration, especially
+	options <tt>RemoteAccessAllowed</tt>, <tt>AuthenticationEnabled</tt>,
+	and <tt>RegisteredUsers</tt>.
+      </p>
+    </div>
+  </div>
 </body>
 
 </html>

--- a/OrthancExplorer/explorer.js	Thu Oct 03 13:44:08 2019 +0200
+++ b/OrthancExplorer/explorer.js	Fri Oct 04 17:41:43 2019 +0200
@@ -79,6 +79,11 @@
         $tree.tree('openNode', event.node, true);
     }
   );
+
+  // Inject the template of the warning about insecure setup as the
+  // first child of each page
+  var insecure = $('#template-insecure').html();
+  $('[data-role="page"]>[data-role="content"]').prepend(insecure);
   
   currentPage = $.mobile.pageData.active;
   currentUuid = $.mobile.pageData.uuid;
@@ -388,6 +393,14 @@
                                 .text(s.Name)
                                 .append(' » '));
       }
+
+      // New in Orthanc 1.5.8
+      if ('IsDefaultUser' in s &&
+          s.IsDefaultUser) {
+        $('.warning-insecure').show();
+      } else {
+        $('.warning-insecure').hide();
+      }
     }
   });
 });

--- a/OrthancServer/OrthancRestApi/OrthancRestSystem.cpp	Thu Oct 03 13:44:08 2019 +0200
+++ b/OrthancServer/OrthancRestApi/OrthancRestSystem.cpp	Fri Oct 04 17:41:43 2019 +0200
@@ -53,11 +53,14 @@
  
   static void GetSystemInformation(RestApiGetCall& call)
   {
+    ServerContext& context = OrthancRestApi::GetContext(call);
+
     Json::Value result = Json::objectValue;
 
     result["ApiVersion"] = ORTHANC_API_VERSION;
     result["Version"] = ORTHANC_VERSION;
     result["DatabaseVersion"] = OrthancRestApi::GetIndex(call).GetDatabaseVersion();
+    result["IsDefaultUser"] = context.IsDefaultUser();  // New in Orthanc 1.5.8
 
     {
       OrthancConfiguration::ReaderLock lock;
@@ -72,7 +75,7 @@
 
 #if ORTHANC_ENABLE_PLUGINS == 1
     result["PluginsEnabled"] = true;
-    const OrthancPlugins& plugins = OrthancRestApi::GetContext(call).GetPlugins();
+    const OrthancPlugins& plugins = context.GetPlugins();
 
     if (plugins.HasStorageArea())
     {

--- a/OrthancServer/ServerContext.cpp	Thu Oct 03 13:44:08 2019 +0200
+++ b/OrthancServer/ServerContext.cpp	Fri Oct 04 17:41:43 2019 +0200
@@ -239,7 +239,8 @@
     done_(false),
     haveJobsChanged_(false),
     isJobsEngineUnserialized_(false),
-    metricsRegistry_(new MetricsRegistry)
+    metricsRegistry_(new MetricsRegistry),
+    isDefaultUser_(false)
   {
     {
       OrthancConfiguration::ReaderLock lock;

--- a/OrthancServer/ServerContext.h	Thu Oct 03 13:44:08 2019 +0200
+++ b/OrthancServer/ServerContext.h	Fri Oct 04 17:41:43 2019 +0200
@@ -220,6 +220,7 @@
     bool saveJobs_;
 
     std::auto_ptr<MetricsRegistry>  metricsRegistry_;
+    bool isDefaultUser_;
 
   public:
     class DicomCacheLocker : public boost::noncopyable
@@ -402,5 +403,15 @@
     {
       return *metricsRegistry_;
     }
+
+    void SetDefaultUser(bool isDefaultUser)
+    {
+      isDefaultUser_ = isDefaultUser;
+    }
+
+    bool IsDefaultUser() const
+    {
+      return isDefaultUser_;
+    }
   };
 }

--- a/OrthancServer/main.cpp	Thu Oct 03 13:44:08 2019 +0200
+++ b/OrthancServer/main.cpp	Fri Oct 04 17:41:43 2019 +0200
@@ -832,8 +832,8 @@
         if (httpServer.IsRemoteAccessAllowed() &&
             !authenticationEnabled)
         {
-          LOG(WARNING) << "Remote access is enabled while user authentication is disabled, "
-                       << "make sure this does not affect the security of your setup";
+          LOG(WARNING) << "====> Remote access is enabled while user authentication is explicitly disabled, "
+                       << "make sure this does not affect the security of your setup <====";
         }
       }
       else if (httpServer.IsRemoteAccessAllowed())
@@ -857,8 +857,35 @@
       if (httpServer.IsAuthenticationEnabled() &&
           !hasUsers)
       {
-        LOG(WARNING) << "HTTP authentication is enabled, but no user is declared, "
-                     << "check the value of configuration option \"RegisteredUsers\"";
+        if (httpServer.IsRemoteAccessAllowed())
+        {
+          /**
+           * Starting with Orthanc 1.5.8, if no user is explicitly
+           * defined while remote access is allowed, we create a
+           * default user, and Orthanc Explorer shows a warning
+           * message about an "Insecure setup". This convention is
+           * used in Docker images "jodogne/orthanc",
+           * "jodogne/orthanc-plugins" and "osimis/orthanc".
+           **/
+          LOG(ERROR) << "====> HTTP authentication is enabled, but no user is declared. "
+                     << "Creating a default user: Review your configuration option \"RegisteredUsers\". "
+                     << "Your setup is INSECURE <====";
+
+          context.SetDefaultUser(true);
+
+          // This is the username/password of the default user in Orthanc.
+          httpServer.RegisterUser("orthanc", "orthanc");
+        }
+        else
+        {
+          LOG(WARNING) << "HTTP authentication is enabled, but no user is declared, "
+                       << "check the value of configuration option \"RegisteredUsers\"";
+        }
+      }
+      else
+      {
+        // This setup is secure
+        context.SetDefaultUser(false);
       }
       
       if (lock.GetConfiguration().GetBooleanParameter("SslEnabled", false))