The world is changing. Established truths just a few years ago are no longer relevant. The means to carry out cyber attacks that used to be reserved for a few, or were mere academic ideas, are accessible to more and less competent attackers. At the same time political development has dramatically increased exposure. An increasing number of businesses therefore need the kind of effective protection previously only used by defense forces and intelligence agencies. Threats that recently were unlikely are likely now.
Vulnerabilities in standard products
Fact: vulnerabilities are implanted in standard products. These vulnerabilities can be exploited for criminal and military purposes. Statistics on detected malicious code show they currently exceed 700 million versions (https://www.av-test.org/en/statistics/malware/#tab-6913-1). Beyond the statistics, unexplored threats are just waiting to be used.
Taking this into account, continuing the prevailing patch and update strategy will not lead to any improvement as it is unlikely that all holes can be patched this way. By definition, only detected holes can be patched – undetected ones remain as latent threats regardless how rigid the patch and update strategy.
Logical or physical separation?
By utilising logical separation with for instance VLAN, and otherwise sharing hardware for storage, networking and firewalls, logical separation is achieved. This is positive – but can lead to a false sense of security.
Systems solely based on this kind of logical separation pose a high risk. Just one small mistake, intentional or accidental, in one of the components gives the attacker the go ahead to create havoc inside the system. In a world where vulnerabilities are actively implanted in many systems, this design philosophy offers too large a risk.
A major difference between logical and physical separation is that the latter also provides protection against undetected vulnerabilities. And in an environment where undetected threats are highly likely, it is necessary to use physical separation as part of the protection.
Combining logical and physical separation
By subdividing systems into zones, VLAN can be used in the zones and physical separation can be used at zone borders. This way, the attacker has to break through zone border protection – instead of simply entering the back door. Furthermore, risks are significantly reduced when zone border protection is based on white listing information – i.e. import and export of data is controlled and without packaging (= without transport protocols).
Security is always a balance between function and safety. It is easy to build safe systems without function – and vice versa. The real art is creating systems that deliver both.