diff --git src/runner.c src/runner.c
index 493fcda..fbf04d2 100644
--- src/runner.c
+++ src/runner.c
@@ -103,8 +103,12 @@ runas(RUNNER this)
     return FALSE;
   }
 
+  if (setgroups(0,0) != 0){
+      NOTIFY(ERROR, "Dropping supplementary group privileges failed.");
+      return FALSE;
+  }
   if (setgid((long)this->grp.gr_gid) != 0) {
-    NOTIFY(ERROR, "Unable to runas group: %s [%ld]", this->grp.gr_name, (long)this->grp.gr_gid);
+    NOTIFY(ERROR, "Unable to run as group: %s [%ld]", this->grp.gr_name, (long)this->grp.gr_gid);
     return FALSE;
   }
   if (setuid((long)this->pwd.pw_uid) != 0) {