With recent news of Singapore disconnecting its government networks from internet access, and now requiring civil servants to use separate computers, I was asked to comment on the security issues this cybersecurity segregation will cause.
Deciding to disconnect from the Internet is clearly a difficult decision and more than likely a result of a reaction to a painful situation. Nobody makes that kind of decision and expects a good reaction. This is not without precedent, however. In North Korea, all websites are under government control. In Cuba, the only access points to the Internet are at government controlled facilities. China blocks sites and actively filters content. If you haven’t looked into this, you’re likely to be shocked by how common this actually is. Take a look at this Wikipedia page discussing this topic https://en.wikipedia.org/wiki/Internet_censorship. There are a number of approaches that are used including IP address blocking, Domain Name redirection, censorship and content and search modification or removal.
As draconian as all of this may seem, it is not uncommon to restrict access, it’s usually just a question of degree. For example, many companies deploy technologies that block access to certain sites from within the corporate network environment. Some ISPs, whether you are aware of this or not, block access to well-known malware sites to reduce the amount of time they have to spend helping their customers recover from infections.
To be completely safe from unwanted viruses, Trojan horses and other malware the only thing you can do is not connect to the Internet at all. Everybody knows this which is why many companies that provide software – such as the major browsers – that help you traverse the Internet, include functionality to help you do that as safely as possible.