diff --git a/infrastructure.yml b/infrastructure.yml
index edf731a..a4fba49 100644
--- a/infrastructure.yml
+++ b/infrastructure.yml
@@ -39,7 +39,7 @@ Resources:
         SecretStringTemplate: '{"username": "app_user"}'
         GenerateStringKey: password
         PasswordLength: 30
-        ExcludeCharacters: '"@/\'
+        ExcludeCharacters: '"@/\:'
 
   DbCluster:
     Type: AWS::RDS::DBCluster