Keeping your Unix system secure is an ongoing responsibility.
Different systems and vendors have different strategies for
distributing updates and bug fixes. You must find out how this
information is distributed for your system, and you must keep up to
Be sure that you get your updates from a reliable source. After you
have installed your updates, continue to monitor mailing lists and
web sites to make sure that the updates themselves have not been
compromised—there are a growing number of cases in which people
have installed security updates that actually contained
vulnerabilities or full-blown Trojan horses. Ultimately, vigilance is
the only way to protect yourself and your computer.