The Place of Pen Testing in the Infosec Strategy
The subject of network penetration testing, as distinct from application security testing, has been given petabytes of coverage since the late 90s, but in terms of how businesses approach network penetration testing, there are still severe shortcomings in terms of return on investment.
A pre-qualifier to save the reader some time: if your concern in security is purely compliance, you need not read on.
Going back to the birth of network penetration testing as a monetized service, we have gone through a transition period of good ground level skills in the mid to late 90s but poor management skills, to just, well...poor everything. This is in no way a reflection on the individuals involved.
With the analysts doing the testing, as a result of modern testing methodology and conditions, the tests are not conducive to driving the analyst to learn deep analytical skills. For managers - the industry as a whole hasn't identified the need to acquire managers who have "graduated" from tech-centric infosec backgrounds. The industry is still young and still making mistakes.
One thing has remained constant through the juvenile years of the industry and that has been poor management. The erosion of decent analytical skills from network penetration testing is ubiquitous apart from a few niche areas (and the dark side) - but this is by and large a consequence of bad management - and again is more of a reflection on the herd-mentality / downward momentum of the industry in general rather than the individuals.
Managers need to have something like a good balance of business acumen and knowledge of technical risks, but in security, most of us still think it's OK to have managers who are heavily weighted towards the business end of the scale.
Several changes took place in service delivery around the early 2000s. One was the imposition of testing restrictions which reduced the effectiveness of testing. When the analysts explained the negative impact of the restrictions (such as limited testing IP ranges, limited use of exploits on production systems, and fixed source IP ranges), the message was either misunderstood by their managers, and/or mis-communicated to the clients who were imposing the restrictions.
So the restrictions took hold. A penetration test that is so heavily restricted can in no way come even close to a simulated attack or even a base level test.
The other factor was improved firewall configurations. There was one major aspect of network security that did improve from the mid 90s until today, and that was firewall configurations. With improved firewall configurations came fewer attack channels, but the testing restrictions had a larger impact on the perceived value of the remote testing service. Improved firewalls may have partly been a result of the earlier penetration tests, but the restrictions turned the testing engagements into an unfair fight.
There were wider forces at work in the security world in the early 2000s which also contributed to the loss of quality from penetration testing delivery, but these are beyond the scope of this article. For all intents and purposes, penetration testing became such a low quality affair that clients stopped paying for it unless they were driven by regulations to perform periodic tests of their perimeter "by an independent third party" - and the situation that arose was one where clients cared not a lot about quality.
This lack of interest was passed on to service providers who in some cases actually reprimanded analysts for trying to be well...analytical. Reason? To be analytical is to retard, and to retard is to reduce profits. Service providers were now a production line for poor quality penetration tests.
So I explained enough about the problems and how they came to be. To be fair, i am not the only one who has identified these issues, its just that there aren't so many of us around these days who were pen testers back in the 90s, and who are willing to put pen to paper on these issues.
I think it should be clear by now that a penetration test with major restrictions applied has only the value that comes from passing the audit. Apart from that? It's a port scan. Anything else? Not in most cases.
Automated tools are used heavily and tools such as vulnerability scanners never were more than glorified port scanners anyway. This is not because the vendors have done a poor job (although in some cases they have), it comes from the nature of remote unauthenticated vulnerability assessment - it's almost impossible to deduce anything about the target, aside from port scanning and grabbing a few service banners.
But... perhaps with the spate of incidents that has been reported as being a 2010-on phenomena (which has really always been prevalent all through the 2000s) there might be some interest in passing the audit, PLUS getting something else in return for the investment.
For this discussion we need to assume utopic conditions. Anything other than unrestricted testing (which also includes use of zero days - another long topic which i'll side-step for now), delivered by highly skilled testers (with hacker-like skills but not necessarily Hackers), will always, without fail, be a waste of resources.
The key here is really in the level of knowledge of internal IT and security staff at the target network under testing.
They realistically have to know everything about their network - every nook and cranny, every router, firewall, application, OS, and how they're all connected. A penetration test should never be used to substitute this knowledge. Typical testing engagements from my experience are carried out with 3 to 4 analysts over a period of a maximum of 2 weeks.
This isn't enough time to have some outside party teach target staff all they need to know about their own private network. Indeed in most cases, one thousand such tests would be insufficient.
In the scenario where both client staff and testers are sufficiently skilled-up, then a penetration test has at least the potential of delivering good value on top of just base compliance.
A test under these conditions we can then perhaps find the slightest cracks in the armor - areas where the client's IT and security staff may have missed something - a misconfiguration, unauthorized change, signs of a previous incident that went undetected, a previously unknown local privilege escalation vector - but the important point is that in most cases there won't be the white noise of findings that comes from the case where there are huge holes in the network.
Under these latter conditions, the test also delivers value, but the results are deceptive. Huge holes are uncovered, with huge holes probably still remaining.
The perimeter has now shifted. User workstation subnets are rightly being seen by many as having been owned by the bad guys, with the result that the perimeter has now shifted into RFC 1918 private address space. So now there can also be an emphasis on penetration testing of critical infrastructure from user workstation subnets. But again, lack of knowledge of internal configurations and controls just won't do.
Whatever resources are devoted to having external third parties doing penetration testing will have been wasted if there is little awareness of internal networks on behalf of the testing subject. There at least has to be detailed awareness of available OS and database security controls and the degree to which they have been applied. Application security - it's a story for another day, and one which doesn't massively affect any of my conclusions here.
Of course there's a gaping hole in this story. I have spoken of skill levels on behalf of the penetration testing analysts and the analysts on the side of the testing subject. But how do we know who is qualified and who is not qualified?
Well, this is the root of all of our problems today. Without this there is no trust. Without a workable accreditation structure, testers can fail to find any reportable findings and accordingly be labeled clowns.
Believe it or not, there is a simple solution here, but this also is too wide a subject to cover here... later on that one!