Higher security in terms of discretionary access control only translates to higher isolation of user contexts. Within a user context, any application is free to do whatever unprivileged action it requires to do its job.
This would limit the attack vector to all protocol action performed before login. Unless you're too stupid to implement CRC32 correctly, I'd say this is a non-issue.
The kernel is always the ultimate authority in the system. If it decides that root isn't the ueber-privileged user any more, it can enforce various limitations. One is that the kernel's logging facility is completely isolated, and all privileges that root could use to get access to kernel memory or compromising the kernel are removed. That is, root might still overwrite the privileges of any user, can change the system time, can debug other processes, can read disks in raw mode etc. but he can't load any drivers, do any kernel debugging, change the RTC time, write to the disk in raw mode, or bypass access checks on the kernel's files and objects.