Posted by Roblimo on Fri May 30, 2003 11:40 AM
from the eating-script-kiddies-for-breakfast dept.
4) Stepping into a network security career
by Anonymous Coward
I'll be graduating this month with a shiny new BS in Computer Science. I've done plenty of Unix sysadmin work throughout college and even deployed some high-interaction honeynets. I'm very interested in network security and systems programming. Do you have any advice for people in my situation who want to head into a career in network security?
Fyodor
Congratulations on your graduation! Unfortunately (for newcomers), the security field is one that often expects substantial experience and references. This is partly because these jobs require extraordinary trust, and also because of an aversion to mistakes. Everyone makes mistakes, but they can be extraordinarily costly in security and neophytes tend to make more of them. But don't lose hope! Talented security minds are still in very high demand, just be aware that you will have to work even harder to prove yourself.
Here are my suggestions for anyone starting out in network security, whether for fun or profit:
Step 1: Learn everything you can
1. You may wish to start with reading a general overview of security, such as Practical Unix and Internet Security 3rd Edition.
2. Reading alone won't teach you much. Hands-on experience is critical, so I would set up at least a basic test network. At the very minimum you should have a Unix box or two and a Windows machine (because these are very common in the real world). You can use very cheap machines, or even emulate a large network with virtualization software such as VMWare.
3. Next you should learn more about how attacks are performed. Take a look at the excellent and free Open Source Security Testing Methodology Manual (OSSTMM). This document aims to provide a comprehensive framework for security testing. But it mostly lists tasks to perform, without specifying how to do so. You will gain a lot from this manual if you research the tasks you don't know how to complete, and if you actually try performing the tasks on your test network. If this manual is too curt or hard to follow, you could try a more verbose book on vulnerability assessment, such as Hacking Exposed 4th Edition.
4. Now that you understand many of the general security ideas, it is time to get current. This is one area that has actually become easier in the last decade. The thinking used to be that vulnerability information should only be distributed to well-known and trusted administrators and security researchers through private digests such as Zardoz. This was a disaster for many reasons, and the full disclosure movement was born. In the last couple of years things have started to shift toward more limited ("responsible") disclosure and there is also a disturbing pay-money-for-early-disclosure trend. But information is still much more available than it used to be. Most of the news is carried on mailing lists, and I archive the ones I consider the best at Lists.Insecure.Org. You must subscribe to Bugtraq, and I would also highly recommend pen-test, vuln-dev, and security-basics. Read at least the last 6-12 months of archives. Choose other lists that correspond to your interests. SecurityFocus also offers a security-jobs list which is an excellent resource for finding jobs or just understanding what employers desire.
There are two major reasons for reading Bugtraq. One is that you must react quickly to new vulnerabilities by patching your servers, notifying your clients, etc. You can get this by simply scanning the subject lines or advisory summaries for bugs that directly apply to you. But then you will miss out on another crucial purpose of Bugtraq. Actually understanding a vulnerability helps you defend against it, exploit it, and identify/prevent similar bugs in the future. When you are lucky, the advisory itself will provide full details on the bug. Check out this excellent recent advisory by Core Security Technologies. Note how they describe exactly how the Snort TCP Stream Reassembly vulnerability works in detail and even include a proof-of-concept demonstration. Unfortunately, not all advisories are so forthcoming. For bugs in Open Source software, you can understand the problem by reading the diff. The next step is to actually write and test an exploit. I would recommend writing at least one for each general class of bug (buffer overflow, format string, SQL injection, etc.) or whenever a bug is particularly interesting.
Be sure to read the latest issues of Phrack and the research papers posted to the mailing lists. Send your comments and questions to the authors and you may start interesting discussions. Read well-regarded books on the security topics that interest you most.
I can't emphasize enough that you should intersperse hands-on work with all of this reading. Install unpatched RedHat 8 (or whatever) and run Nmap and Nessus against it. Then compromise it remotely, maybe via the latest Samba hole. Start out with a prewritten exploit from Bugtraq, which isn't quite as easy as it sounds. You may have to modify the 'sploit to compile, brute force the proper offset, etc. Then break in again using a different technique, and your own exploit. Install Ethereal and/or tcpdump and ensure you understand the traffic on your network during both your exploitation and normal network activity. Install Snort on an Internet-facing machine and watch the attacks and probes you'll experience. Wander around your neighborhood with Kismet, Netstumbler, or Wellenreiter on your Laptop or PDA to look for open WAPs. Install DSniff and execute an active MITM attack on an SSH or SSL connection between two of your computers. Take a look at my Top 75 Tools List and ensure you understand what each does and when it would be useful. Try out as many as you can.
5. Take a vacation, or at least a weekend camping! You deserve it! The steps above would probably take at least 3-12 months full-time, depending on your motivation level and the depth and breadth of your research.
Step 2: Now apply your newfound knowledge
Now you have learned enough to be dangerous. At this point, you would have little trouble obtaining most certifications, after studying the specifics of each topic. If your main goal is to find a job quickly, perhaps adding these extra feathers to your cap might be worthwhile. But I think your best bet is to prove your knowledge by joining and contributing to the security community. While this does indeed help others, it isn't an entirely selfless act. It improves your skills, leads to important contacts, and demonstrates your knowledge and ability in a constructive way. The latter is important if securing a career is one of your goals. These steps should also be fun! If not, perhaps you should keep looking at other fields. Here are some ideas:
Start participating with insightful comment and answers on the mailing lists. This is very easy and serves as a great learning experience, way to meet people, and garners some name recognition. If a security manager with a stack of 60 resumes recognizes your name, that is a huge win!
When a new worm or a big new vulnerability comes out, everyone wants to know the details. If you stay up all night disassembling the worm/patch and write the first comprehensive analysis, many folks will find that valuable. And you will learn a lot. Let your first priority be quality - if someone beats you to it, just compare your results with theirs to see if you (or they) missed (or misinterpreted) anything. You can also post your own exploits, although that is more of a political hot potato.
Attending security conferences is a great way to learn, party with fellow hackers, and network (in every sense of the word). Much better is to speak at these conferences. This field changes rapidly so there are always new topics and technologies to discuss. You don't have to be a well-known expert with a long history - just learn your topic well and put in the effort for a quality presentation. You could present at Defcon, at one of the more commercial events, or at a smaller regional con like ToorCon, CodeCon, Hivercon, etc. Among other advantages (often free admission/travel/hotel), this is a great way to meet people with similar interests. I spoke at the latest CanSecWest and have submitted a proposal for the next Defcon.
Now that you've seen and understand a wide variety of software vulnerabilities from your Bugtraq research, start finding your own. You can start by downloading any PHP app from Sourceforge. Most of those are hopelessly vulnerable to Cross-Site-Scripting, SQL injection, and/or remote code execution by "remote include" directives. Many (if not most) Windows shareware daemons are also vulnerable to simple buffer overflows and format-string bugs. Notify the authors and then write an advisory. After a few of these "easy targets", try breaking some more widely deployed programs.
Write a security tool! I could list some suggestions, but by this point you will have many of your own ideas as to what is needed. Scratch an itch.
I hope this helps. If you want more suggestions, Ask Slashdot. From that story, I found this post particularly insightful, especially the emphasis on "people skills". I don't claim to have any, but understand the value :).
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