diff --git a/contrib/deb/generate.sh b/contrib/deb/generate.sh
index efab56e7..b4c5f268 100644
--- a/contrib/deb/generate.sh
+++ b/contrib/deb/generate.sh
@@ -74,6 +74,7 @@ etc/apparmor.d/* etc/apparmor.d
 EOF
 cat > /tmp/$PKGNAME/debian/postinst << EOF
 #!/bin/sh
+umask 077
 
 if ! getent group yggdrasil 2>&1 > /dev/null; then
   groupadd --system --force yggdrasil || echo "Failed to create group 'yggdrasil' - please create it manually and reinstall"