Tuesday, December 15, 2009

Computer security badness hierarchy revisited

Last week was the last week of my SANS mentor class for Hacker Techniques, Exploits and Incident Handling. Hopefully my students will try out for certification and pass gloriously.

As always, we wrapped the 10-week teaching cycle up with the ever-entertaining capture-the-flag (CtF) session that really drives home a few key points. In a previous blog post (computer security badness hierarchy. January 13, 2009), I argued that when we focus on our responsibility for securing information technology
(as part of a much larger socio-economic information system), information security practitioners really only have to worry about a few types of things: Bad Users, Bad Configuration, and Bad Software.

Most CtF's are completely in line with my hierarchy and by using tools such as nmap and metasploit and by leveraging exploit code that is readily available in places like the Offensive Security Exploit Database (formerly known as Milw0rm), most challenges in "hack labs" can be solved easily.

The major exploitable categories are typically credential re-use (bad users), unpatched software (bad software), running unnecessary services (bad configuration) and lack of port filtering (bad configuration), and can be found on most (if not all) enterprise networks. Of course, there are many more attack vectors (think "Web" and "end-point").

As a security practitioner, there are few tools more valuable than a well-designed and fully implemented vulnerability management program. When possible, it is nice to drop the $100K+ to purchase one of the commercial suites, but by ensuring that all your computers (servers, desktops and laptops) are configured according to a hardening template and that they receive all patches in a timely fashion is already a major gain. Put on top of that a decent (current) anti-malware package, and you have a nice start.

Do not underestimate the complexity of "just" doing this. If you haven't started this yet, get going. If you have started, but don't think you're done: welcome to the club ;)

If you are embarking on such a project, think about collecting some metrics about how well you are doing it so you can measure progress and define success. Think of numbers like: percentage of end-points that have been patched appropriately, percentage of end-points with current anti-malware software, average lag between publication of vulnerabilities and completion of roll-out, number of end-points in compliance with the hardening template, etc.



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