This entry from Security Metrics is followed up with the following CVE: CVE-2002-0510.
ClearCenter does not consider this to be a security bug.
There are multiple ways to mask your version of Linux and various underlying services. ClearCenter does not consider this to be particularly critical nor that it provides a specific advantage to a hacker.
No action required. See http://www.infosecwriters.com/text_resources/pdf/nmap.pdf