diff --git a/main.tf b/main.tf
index 10bac59..650c5a8 100644
--- a/main.tf
+++ b/main.tf
@@ -41,6 +41,7 @@ module "vpc" {
 
 ### create a security group
 module "web_server_sg" {
+  version             = "5.2.0"
   source              = "terraform-aws-modules/security-group/aws//modules/http-80"
   name                = "${local.name}-web-server-sg"
   description         = "Security group for web server of ${local.name}"