diff --git a/k5test/_utils.py b/k5test/_utils.py
index 7a94e12..e289fac 100644
--- a/k5test/_utils.py
+++ b/k5test/_utils.py
@@ -97,8 +97,9 @@ def _decide_plugin_dir(dirs):
 
 def _find_plugin_dirs_installed(search_path):
     try:
-        options_raw = get_output('find %s/ -type d '
-                                 '-path "*/krb5/plugins"' % search_path,
+        options_raw = get_output('find %s/ -type d \( ! -executable -o ! -readable \) '
+                                 '-prune -o '
+                                 '-type d -path "*/krb5/plugins" -print' % search_path,
                                  stderr=subprocess.STDOUT)
     except subprocess.CalledProcessError:
         options_raw = None