Want Better Infosec? Limit Functionality and Visibility

We humans are great at exploiting and expanding new technologies, but we often jump in with both feet before we fully understand the ramifications what we are doing. I cite the Internet itself. The ARPANET and the TCP/IP suite were entities designed to enable and enhance communications between people, not restrict them. The idea of security was ill considered from the beginning and was never a part of the design. Unfortunately, by the time we realized this fact, the Internet was already going great guns and it was too late to change it.

The same thing happened with personal computers. Many businesses found it was cheaper and easier to exploit this new technology than to stay with the main frame. So they jumped right in, bought off the shelf devices and operating systems, networked them together and voila! Business heaven!

Unfortunately, there was a snake in the garden. These computers and operating systems were not designed with businesses, and their attendant need for security, in mind. Such commercial systems have all kinds of functionalities and “features” that are not only useless for business purposes, they are pure gold for hackers.

As with the Internet, once people understood the security dangers of using these products, their use was ingrained and change was practically impossible. All we can do now, at least until these basic flaws are corrected, is try to work around them. One way to make a good start at this is to limit what these systems can do as much as is possible; if it doesn’t have a business function it should be turned off or removed.

For example, why should most employees have the ability to browse the Internet or check their social networking sites on their business systems? Few employees actually need this functionality, and those who do should be strictly limited and monitored. Almost all job descriptions could get by with a handful of websites (white listing), and those that truly do need full Internet accessibility should have their own subnet. How many employees in these times don’t have a smart phone in their pocket? Can’t they go to Facebook or check their bank account on that?

There are also many other examples of limiting the functionality of business devices and applications. USB ports, card readers and disc players are not necessary for most job descriptions. How about all those lovely services and features found in many commercial software applications and operating systems? Why not turn off as many of those as possible. There are lots of things that can be disabled using Active Directory.

In addition to limiting what systems and people can do, it is also a very good security idea to limit what they can see. Access to information, applications and devices should be strictly based on need to know. And in addition to information, users should not be able to see across the network. Why should a user in workstation space have the ability to see into server space? Why should marketing personnel have access to accounting information? This means good network segmentation with firewalls, logging and monitoring between the segments. Do whatever you can to limit what systems can see and do and I guarantee you will immediately see the security benefits.

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