Posted by Martijn Grooten on Feb 20, 2018
Though not even a year and a half old, the UK's National Cyber Security Centre (NCSC) has already managed to make a name for itself through its practical advice and guidance on many security topics.
Earlier this month, the Centre published guidance on lateral movement: the techniques used by an attacker to move through a network once they have gained a foothold.
We tend to underestimate how well many organisations have protected their perimeter: firewalls, as well as email and web security, have become standard and do a good job of keeping most attacks at bay. But at the same time, we often forget that, on the inside, many networks look like open-plan offices and it's often relatively trivial for an attacker, once inside a network, to move to other, more valuable, targets.
That's why I think NCSC's advice is very helpful – and I'd like to add two more pieces of advice of my own.
The first is to include devices that are not directly connected to the Internet in your organisation's patching plan. Vulnerabilities in such devices aren't easily exploited and thus one can easily have an unpatched server or desktop running for years without any incidents – which can give a false sense of security.
That this sense of security really is false was an important lesson learned from WannaCry, the malware that exploited a patched vulnerability in Microsoft's SMB protocol, though which it spread quickly within many organisations' networks. The exploit used by WannaCry has since found its way into other kinds of malware.
The second piece of advice is to deploy canaries: digital assets that come in various forms, from documents to (virtual) servers, and that send an alert when someone accesses them.
Unlike honeypots, the goal of these canaries is not to learn more about attackers' methods, but simply to be alerted when someone with possibly malicious intent has gained access to your network. For, as NCSC rightly points out: "you should assume that an attacker with sufficient time and resources will eventually be successful". It is how you detect and respond to such attacks that will make the difference.