This means the intruder would need root access to insert a module. If the intruder gains root access, there are more serious things to worry about than whether he will load a module. Modules are for dynamically loading support for a particular device that may be infrequently used. On server machines, or firewalls for instance, this is very unlikely to happen. For this reason, it would make more sense to compile support directly into the kernel for machines acting as a server.
Modules are also slower than support compiled directly in the kernel.
See Root Security . This is done intentionally to prevent remote users from attempting to connect via telnet to your machine as root , which is a serious security vulnerability, because then the root password would be transmitted, in cleartext, across the network. This has several advantages. The other advantage is that as the administrator, you can enable or disable accounts without everyone knowing the status of other users' accounts. Since you're interested in securing your passwords, perhaps you would also be interested in generating good passwords to begin with.