Security defenses don’t improve our understanding of the root causes of data breaches

Why is this so? Because when you defend against a data breach – you do not necessarily understand the vulnerabilities that can be exploited.
If do not understand the root causes of your vulnerabilities, how can you justify and measure the effectiveness of your defensive measures?
Let me provide you with an example.
Conventional IT security practice says that you must install a firewall in front of a server farm.

Firewalls prevent the bad guys from getting in. They don’t prevent sensitive data assets from leaving your network during a data breach.

If you have a dozen servers, running Ubuntu 12.04 with the latest patches, hardened and only serving responses to requests on SSH and HTTPS services not only is there no added value in a firewall but installing and maintaining a firewall will be a waste of money that doesn’t defend against a data breach.

First of all – defenses are by definition, not a means of improving our understanding of strategic threats. Think about the Maginot Line in WWI or the Bar-Lev line in 1973. Network and application security products that are used to defend the organization are rather poor at helping us understand and reduce the operational risk of insecure software.

Second of all – it’s hard to keep up. Security defense products have much longer product development life cycles then the people who develop day zero exploits. The battle is also extremely asymmetric – as it costs millions to develop a good application firewall that can mitigate an attack that was developed at the cost of three man months and a few Ubuntu workstations. Security signatures (even if updated frequently) used by products such as firewalls, IPS and black-box application security are no match for fast moving, application-specific source code vulnerabilities exploited by attackers and contractors.
Remember – that’s your source code, not Microsoft.
Third – threats are evolving rapidly. Current defense in depth strategy is to deploy multiple tools at the network perimeter such as firewalls, intrusion prevention and malicious content filtering. Although content inspection technologies such as DPI and DLP are now available, current focus is primarily on the network, despite the fact that the majority of attacks are on the data – customer data and intellectual property.
The location of the data has also become less specific as the notion of trusted systems inside a hard perimeter has practically disappeared with the proliferation of cloud services, Web 2.0 services, SSL VPN and convergence of almost all application transport to HTTP.
In summary – before handing over a PO to your local information security integrator – I strongly suggest a systematic threat analysis of your systems. After you have prioritized set of countermeasures – you’ll be buying, but not necessarily what he’s selling.