PCI – Going Beyond the Standard: Part 11, Vulnerability Management

For those of you errr… fortunate enough to be have been performing PCI assessments as long as I have, you will have noticed the ‘progress’ the DSS has made in terms of turning ‘just patching’ into more of a risk based approach to threats. Yes, it’s about time, and no, it has not gone far enough to be truly effective, but it should go to show just how important this subject is.

v1.1 of the DSS didn’t contain the phrase ‘risk-based’ at all, v1.2 and v2.0 say that organisations “MAY consider applying a risk-based approach to prioritise their patch installations.”, then finally in v3.0 says; “6.1 Establish a process to identify security vulnerabilities, using reputable outside sources for security vulnerability information, and assign a risk ranking (for example, as “high,” “medium,” or “low”) to newly discovered security vulnerabilities.

This only took 8 years.

Unfortunately, it’ll be 3 more years before they can make any additional improvements, and when you consider how far they are already behind, and the rapidly worsening threat landscape, you simply cannot afford to do the PCI minimums here.

Vulnerability Management is the overarching process whereby a significant number of other processes are combined into a method for the never-ending examination and remediation of threats to your business. Everything from risk assessment, to asset management, to configuration standards, to change control, to patching, to vulnerability scanning to penetration testing, to monitoring and incident response, all combine into a life cycle of knowing your business goals, and enabling both IT and the business side to get there safely.

REAL Governance in other words.

I have already explained [hopefully] why Risk Assessment s and Asset Management are the starting points for a proper vulnerability management program. The rest of my list below will get their own post in due course, but here’s why they are included here:

  1. Configuration Standards – No point trying to manage risk on something that is fundamentally flawed. Don’t get these right and all the vulnerability scanning and penetration testing in the world isn’t going to help. Not to mention your logging and monitoring would be so inundated with false positives as to be rendered ineffective;
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  2. Change Control – Without VERY robust change control even the best initial set-ups can become rapidly insecure. Why make things easier for the bad guys?;
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  3. Patching – For the longest time the PCI DSS focused on the patching of systems, and insisted that all relevant, critical security patches be installed within 30 days. This completely missed the point, and while patching is an important aspect of vulnerability management, relying on reactive security measures is like taking aspirin for a broken leg;
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  4. Vulnerability Scanning & Penetration Testing – I lump these two together not because they are so similar (they aren’t), but because they are complimentary and fall within the same category; Testing. The cycle of constant improvement cannot be maintained if you aren’t testing your security controls and processes in some way. Test, fix, test again, repeat forever;
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  5. Monitoring – For every second of the day, your systems are providing information relevant to their health and security. Ignore these events, or fail to properly interpret these events and you have negated any ability you have to prevent a minor incident from becoming a worse. Unless you are able to baseline a ‘known-good’ environment, you have no idea what ‘bad’ is;
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  6. Incident Response (and Disaster Recovery) – In theory, you should never need Disaster Recovery if your Incident Response is as good as it should be. Without all of the above in place, you don’t have the ability to perform either well.

One of the most common complaints I get from clients is that previous QSAs have insisted that relevant, critical security patches are installed within 30 days. Yes, that’s what the PCI DSS says, but the only reason I can see that this should be a problem is if your Vulnerability Management process is so poor that you cannot show your QSA how installation within one month is actually MORE risky than to not.

There can be many reasons for this, but the inability to test patches and/or get them rolled-out in time are not excuses I would accept.

I have yet to see Vulnerability Management done well, in ANY organisation I have assessed. The pro-active life cycle approach to security, while very difficult to set-up, is nevertheless very simple and far cheaper in the long run that a reactive one. My analogy for this is that it will take me a year before I’m fit enough to ever run a marathon again, but if I had just MAINTAINED my fitness from the last one, it would be a hundred times easier.

The only things in security that stay the same are the basic good practices, vulnerability management is one of those basics.

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