Brindle on Security

For those of you who missed my other Security Anti-Pattern post, an anti-pattern is a commonly reinvented bad solution to a problem. There are many of these in security but one that seems to be occurring quite often these days is path based access control, an access control system that use file paths to refer to objects. To the uninitiated this may seem like a good idea at first, hopefully this blog entry will eradicate such beliefs. Apologies in advance for the length of this post.

Read the rest of this entry

I’ll be the first to say I’m not a policy developer. The process of actually writing policy is not at all interesting to me, fortunately for me there are people like Chris PeBenito, Russell Coker, et al that seem to enjoy this. I am interested, however, in how policies are developed.

There seem to be two schools of thought on this subject: top-down policy development and bottom-up. Top-down policy development is very similar to status quo encapsulation, which I talked about in a previous post, in that it basically means you take a running system and look at it top-down, in its entirety, and develop a policy based on that perspective. Bottom-up policy development, which is historically what SELinux has done, is the opposite; you create policies for individual applications running on a system until the sum of those policies meets the security goals of the system. I’ll try to talk about the advantages and issues with each of these.

Read the rest of this entry