diff --git a/src/Authorization/AuthorizationDataMuxer.php b/src/Authorization/AuthorizationDataMuxer.php
index 475b79c63662b9c1836835cb434cf5acb2251f7b..49705938ccd5275313f954aacb71482524243b9d 100644
--- a/src/Authorization/AuthorizationDataMuxer.php
+++ b/src/Authorization/AuthorizationDataMuxer.php
@@ -23,15 +23,29 @@ class AuthorizationDataMuxer
 
     private function loadUserAttributesFromAuthorizationProvider(?string $userIdentifier, AuthorizationDataProviderInterface $authorizationDataProvider): void
     {
-        $userAttributes = [];
+        $userAttributes = $authorizationDataProvider->getUserAttributes($userIdentifier);
 
-        if ($userIdentifier !== null) {
-            $userAttributes = $authorizationDataProvider->getUserAttributes($userIdentifier);
+        foreach ($authorizationDataProvider->getAvailableAttributes() as $availableAttribute) {
+            if (array_key_exists($availableAttribute, $userAttributes)) {
+                $this->customAttributes[$availableAttribute] = $userAttributes[$availableAttribute];
+            }
         }
+    }
 
-        foreach ($authorizationDataProvider->getAvailableAttributes() as $availableAttribute) {
-            $this->customAttributes[$availableAttribute] = $userAttributes[$availableAttribute] ?? null;
+    /**
+     * Returns an array of available attributes.
+     *
+     * @return string[]
+     */
+    public function getAvailableAttributes(): array
+    {
+        $res = [];
+        foreach ($this->authorizationDataProviders as $authorizationDataProvider) {
+            $availableAttributes = $authorizationDataProvider->getAvailableAttributes();
+            $res = array_merge($res, $availableAttributes);
         }
+
+        return $res;
     }
 
     /**
diff --git a/src/Authorization/DebugCommand.php b/src/Authorization/DebugCommand.php
index ddbc71258ddf719cce3db9e78a9e994e8d02f17b..13c0794efdf062ffa820e025ed8ffba6008d602e 100644
--- a/src/Authorization/DebugCommand.php
+++ b/src/Authorization/DebugCommand.php
@@ -37,32 +37,26 @@ class DebugCommand extends Command implements LoggerAwareInterface
     protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $username = $input->getArgument('username');
-        if ($username === null) {
-            // No username, list all providers
-            $output->writeln("<fg=blue;options=bold>Attributes available for all provider</>\n");
-            $providers = $this->provider->getAuthorizationDataProviders();
-            foreach ($providers as $provider) {
-                $output->writeln('<fg=green;options=bold>['.get_class($provider).']</>');
-                foreach ($provider->getAvailableAttributes() as $attr) {
-                    $output->writeln($attr);
-                }
-                $output->writeln('');
-            }
 
-            // TODO: list all attributes
-        } else {
-            // get all available attributes for a user per provider
-            $output->writeln('<fg=blue;options=bold>Attributes for user "'.$username."\":</>\n");
-            $providers = $this->provider->getAuthorizationDataProviders();
-            foreach ($providers as $provider) {
-                $output->writeln('<fg=green;options=bold>['.get_class($provider).']</>');
-                foreach ($provider->getUserAttributes($username) as $attr => $value) {
-                    $output->writeln($attr.'='.json_encode($value));
-                }
-                $output->writeln('');
-            }
+        // Fetch all attributes first (to get potential log spam first)
+        $providers = $this->provider->getAuthorizationDataProviders();
+        $mux = new AuthorizationDataMuxer($providers);
+        $attrs = $mux->getAvailableAttributes();
+        $all = [];
+        $default = new \stdClass();
+        sort($attrs, SORT_STRING | SORT_FLAG_CASE);
+        foreach ($attrs as $attr) {
+            $all[$attr] = $mux->getCustomAttribute($username, $attr, $default);
+        }
 
-            // TODO: list all attributes
+        // Now print them out
+        $output->writeln('<fg=blue;options=bold>[Authorization attributes]</>');
+        foreach ($all as $attr => $value) {
+            if ($value === $default) {
+                $output->writeln('<fg=green;options=bold>'.$attr.'</> = <fg=magenta;options=bold>\<N/A\></>');
+            } else {
+                $output->writeln('<fg=green;options=bold>'.$attr.'</> = '.json_encode($value));
+            }
         }
 
         return 0;