diff --git a/pkgs/servers/mail/opensmtpd/default.nix b/pkgs/servers/mail/opensmtpd/default.nix
index 7ad5f6e9ad59..d2667597c627 100644
--- a/pkgs/servers/mail/opensmtpd/default.nix
+++ b/pkgs/servers/mail/opensmtpd/default.nix
@@ -31,6 +31,7 @@ stdenv.mkDerivation rec {
       substituteInPlace smtpd/smtpctl.c --replace \
         'if (geteuid())' \
         'if (geteuid() != 0 && !(argc > 1 && !strcmp(argv[1], "encrypt")))'
+      substituteInPlace mk/smtpctl/Makefile.in --replace "chmod 2555" "chmod 0555"
     '';
 
   configureFlags = [