diff --git a/apps/su.cpp b/apps/su.cpp
index 80b1a8a8..a2d9aa56 100644
--- a/apps/su.cpp
+++ b/apps/su.cpp
@@ -148,6 +148,12 @@ Result<int> luna_main(int argc, char** argv)
     {
         signal(SIGTTOU, SIG_IGN);
 
+        if (!strcmp(entry->pw_passwd, "!"))
+        {
+            fprintf(stderr, "%s: %s's password is disabled!\n", argv[0], entry->pw_name);
+            return 1;
+        }
+
         char* pass = getpass();
         if (!pass) return 1;