Index: res/ari/resource_asterisk.c
===================================================================
--- res/ari/resource_asterisk.c	(revision 396920)
+++ res/ari/resource_asterisk.c	(working copy)
@@ -154,7 +154,11 @@
 		return;
 	}
 
-	value = ast_str_retrieve_variable(&tmp, 0, NULL, NULL, args->variable);
+	if (args->variable) {
+		value = ast_str_retrieve_variable(&tmp, 0, NULL, NULL, args->variable);
+	} else {
+		value = NULL;
+	}
 
 	if (!(json = ast_json_pack("{s: s}", "value", S_OR(value, "")))) {
 		ast_ari_response_alloc_failed(response);