The best way to defend against most network vulnerabilities is to deal with the simplest attack vectors, according to Australia’s Defence Signals Directorate (DSD).
The DSD’s analysis has credibility and clout, because it’s based on analysis of real attacks launched against Australian government networks. And according to its latest work, as much as 85 percent of attacks can be addressed with four relatively straightforward defences.
These are, in order: keep applications patched and use the latest version of applications (Flash, the Acrobat PDF viewer, Microsoft office and Java are singled out); patch operating system vulnerabilities; minimize the number of users with administrative access to systems (while making sure that your BOFH doesn’t use an admin account for e-mail and browsing); and whitelist your applications.
Not completely: actually, the DSD includes 35 recommendations. But to knock off the maximum number of attack vectors with the least effort, those four strategies have serious bang-for-buck.
There are others that are worth mentioning – such as whitelisting e-mail content, sanitizing attachments, blocking spoofed e-mail addresses with a sender policy framework, Web content filtering (including HTTPS and SSL domains), multi-factor authentication and so on. But the big four should be everybody’s starting point.
Such advice would hardly be newsworthy, except for one thing: the huge number of successful attacks shows us just how few people can get the basics right.
Interestingly, the DSD research also indicates that attackers are looking for bang-for-buck. The same analysis for 2010 found that the four strategies outlined above would have only repelled 70 percent of attacks. Attackers, it seems, can be just as interested in convenience as those they attack. ®