diff --git a/molecule/settings.py b/molecule/settings.py
index 10f141f..eb46a1e 100644
--- a/molecule/settings.py
+++ b/molecule/settings.py
@@ -62,9 +62,9 @@ class Configuration(dict):
                 "--delete-excluded", "--delete-during", "--numeric-ids",
                 "--recursive", "-d", "-A", "-H"],
             'chroot_compressor_output_file': "livecd.squashfs",
-            'iso_mounter': ["/bin/mount", "-o", "loop", "-t", "iso9660"],
+            'iso_mounter': ["/bin/mount", "-o", "loop,ro", "-t", "iso9660"],
             'iso_umounter': ["/bin/umount"],
-            'squash_mounter': ["/bin/mount", "-o", "loop", "-t", "squashfs"],
+            'squash_mounter': ["/bin/mount", "-o", "loop,ro", "-t", "squashfs"],
             'squash_umounter': ["/bin/umount"],
             'pkgs_adder': ["/usr/bin/equo", "install"],
             'pkgs_remover': ["/usr/bin/equo", "remove"],