Hardening is Hard If You’re Doing it Right

Yes, ladies and gentlemen, hardening is hard. If its not hard, then there are two possibilities. One is that the maturity of information security in the organization is at such a level that security happens both effectively and transparently – its fully integrated into the fabric of BAU processes and many of said processes are fully automated with accurate results. The second (far more likely given the reality of security in 2013) is that the hardening is not well implemented.

For the purpose of this diatribe, let us first define “hardening” so that we can all be reading from the same hymn sheet. When I’m talking about hardening here, the theme is one of first assessing vulnerability, then addressing the business risk presented by the vulnerability. This can apply to applications, or operating systems, or any aspect of risk assessment on corporate infrastructure.

In assessing vulnerability, if you’re following a check list, hardening is not hard – in fact a parrot can repeat pearls of wisdom from a check list. But the result of merely following a check list will be either wide open critical hosts or over-spending on security – usually the former. For sure, critical production systems will be impacted, and I don’t mean in a positive way.

You see, like most things in security, some thinking is involved. It does suit the agenda of many in this field to pretend that security analysis can be reduced down to parrot-fashion recital of a check list. Unfortunately though, some neural activity is required, at least if gaining the trust of our customers (C-levels, other business units, home users, etc) is important to us.

The actual contents of the check list should be the easy part, although unfortunately as of 2013, we all seem to be using different versions of the check list, and some versions are appallingly lacking. The worst offenders here deliver with a quality that is inversely proportional to the prices they charge – and these are usually external auditors from big 4 consultancies, all of whom have very decent check lists, but who also fail to ensure that Consultants use said check list. There are plenty of cases where the auditor knocks up their own garage’y style shell script for testing. In one case i witnessed not so long ago, the script for testing RedHat Enterprise Linux consisted of 6 tests (!) and one of the tests showed a misunderstanding of the purpose of the /etc/ftpusers file.

But the focus here is not on the methods deployed by auditors, its more general than that. Vulnerability testing in general is not a small subject. I have posted previously on the subject of “manual” network penetration testing. In summary: there will be a need for some businesses to show auditors that their perimeter has been assessed by a “trusted third party”, but in terms of pure value, very few businesses should be paying for the standard two week delivery with a four person team. For businesses to see any real value in a network penetration test, their security has to be at a certain level of maturity. Most businesses are nowhere near that level.

Then there is the subject of automated, unauthenticated “scanning” techniques which I have also written about extensively, both in an earlier post and in Chapter Five of Security De-engineering. In summary, the methodology used in unauthenticated vulnerability scanning results in inaccuracy, large numbers of false positives, wasted resources, and annoyed operations and development teams. This is not a problem with any particular tool, although some of them are especially bad. It is a limitation of the concept of unauthenticated testing, which amounts to little more than pure guesswork in vulnerability assessment.

How about the growing numbers of “vulnerability management” products out there (which do not “manage” vulnerability, they make an attempt at assessing vulnerability)? Well, most of them are either purely an expensive graphical interface to [insert free/open source scanner name], or if the tool was designed to make a serious attempt at accurate vulnerability assessment (more of them do not), then the tests will be lacking or over-done, inaccurate, and / or doing the scanning in an insecure way (e.g. the application is run over a public URL, with the result that all of your configuration data, including admin passwords, are held by an untrusted third party).

In one case, a very expensive VM product literally does nothing other than port scan. It is configured with hundreds of “test” patterns for different types of target (MS Windows, *nix, etc) but if you’re familiar with your OS configurations,you will look at the tool output and be immediately suspicious. I ran the tool against a Linux and Windows test target and “packet sniffed” the scanning engine’s probe attempts. In summary, the tool does nothing. It just produces a long list of configuration items (so effectively a kind of Security Standard for the target) without actually testing for the existence of vulnerability.

So the overall principle: the company [hopefully] has a security standard for each major operating system and database on their network and each item in the standard needs to be tested for all, or some of the information asset hosts in the organization, depending on the overall strategy and network architecture. As of the time of writing, there will need to be some manual / scripted augmentation of automatic vulnerability assessment processes.

So once armed with a list of vulnerabilities, what does one do with it? The vulnerability assessment is the first step. What has to happen after that? Can Security just toss the report over to ops and hope for the best? Yes, they can, but this wouldn’t make them very popular and also there needs to be some input from security regarding the actual risk to the business. Taking the typical function of operations teams (I commented on the functions and relationships between security and operations in an earlier post), if there is no input from security, then every risk mitigation that meets any kind of an impact will be blocked.

There are some security service providers/consultancies who offer a testing AND a subsequent hardening service. They want to offer both detection AND a solution, and this is very innovative and noble of them. However, how many security vulnerabilities can be addressed blindly without impacting critical production processes? Rhetorical question: can applications be broken by applying security fixes? If I remove the setuid bit from a root owned X Window related binary, it probably has no effect on business processes. Right? What if operations teams can no longer authenticate via their usual graphical interface? This is at least a little bit disruptive.

In practice, as it turns out, if you look at a Security Standard for a core technology, lets take Oracle 11g as an example: how many of the numerous elements of a Security Standard can we say can be implemented without fear of breaking applications, limiting access for users or administrators, or generally just making trouble-shooting of critical applications a lot less efficient? The answer is: not many. Dependencies and other problems can come from surprising sources.

Who in the organization knows about dependencies and the complexities of production systems? Usually that would be IT / Network Operations. And how about application – related dependencies? That would be application architects, or just generally we’ll say “dev teams” as they’re so affectionately referred to these days. So the point: even if security does have admin access to IT resources (rare), is the risk mitigation/hardening a job purely for security? Of course the answer is a resounding no, and the same goes for IT Operations.

So, operations and applications architects bring knowledge of the complexities of apps and infrastructure to the table. Security brings knowledge of the network architecture (data flows, firewall configurations, network device configurations), the risk of each vulnerability (how hard is to exploit and what is the impact?), and the importance to the business of information assets/applications. Armed with the aforementioned knowledge, informed and sensible decisions on what to do with the risk (accept, mitigate, work around, or transfer) can be made by the organization, not by security, or operations.

The early days of deciding what to do with the risk will be slow and difficult and there might even be some feisty exchanges, but eventually, addressing the risk becomes a mature, documented process that almost melts into the background hum of the machinery of a business.

Share This: