Security isn't a noun, it's a verb; not a product, but a process. Today, learn the hacks involved in reducing the risks involved in offering services on a Unix-based system. This the second part of chapter one in Network Security Hacks, by Andrew Lockhart (ISBN 0-596-00643-8, O'Reilly & Associates, 2004).
Patch security holes in a timely manner to prevent intrusions.
Updating and patching a system in a timely manner is one of the most important things you can do to help protect your systems from the deluge of newly discovered security vulnerabilities. Unfortunately, this task often gets pushed to the wayside in favor of “more pressing” issues, such as performance tuning, hardware maintenance, and software debugging. In some circles, it’s viewed as a waste of time and overhead that doesn’t contribute to the primary function of a system. Coupled with management demands to maximize production, keeping a system up-to-date is often pushed even further down on the to-do list.
Updating a system can be very repetitive and time consuming if you’re not using scripting to automate it. Fortunately, most Linux distributions make their updated packages available for download from a standard online location. We can monitor that location for changes and automatically detect and download the new updates when they’re made available. To demonstrate how to do this on an RPM-based distribution, we’ll use AutoRPM (http://www.autorpm.org).
AutoRPM is a powerful Perl script that allows you to monitor multiple FTP sites for changes. It will automatically download new or changed packages and either install them automatically or alert you so that you may do so. In addition to monitoring single FTP sites, you can also monitor a pool of mirror sites, to ensure that you still get your updates in spite of a busy FTP server. This feature is especially nice in that AutoRPM will monitor busy FTP servers and keep track of how many times a connection to them has been attempted. Using this information, it assigns internal scores to each of the FTP sites configured within a given pool, with the outcome that the server in the pool that is available most often will be checked first.
To install AutoRPM, download the latest package and install it like this:
# rpm -ivh autorpm-3.3-1.noarch.rpm
Although a tarball is also available, installation is a little more tricky than the typical make; make install, and so it is recommended that you stick to installing from the RPM package.
By default, AutoRPM is configured to monitor for updated packages for Red Hat’s Linux distribution. However, you can configure it to monitor any file repository of your choosing, such as one for SuSE or Mandrake.
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