Walk onto a course on operating system security boundaries will delve into the issue of using Windows
systems for illustration as the most popular operating systems and use since Windows is so popular with
users.
We'll spend most of our working hours on protecting this system Microsoft has a well-defined security
policy that will also use as an example to highlight some theoretical aspects Trustworthy Computing
forms a part of Microsoft security policy initiative it was launched in 2002 and its goal is to ensure
the security confidentiality and reliability of data processing.
It is also to find the concept of a Windows security boundary this term relates to protecting users
by sandboxing some areas by separating some operations that are potentially unsafe.
They have to be isolated so they don't run in an uncontrolled manner and affect other components of
the system environment and other users.
The simplest boundary might look like the picture below boundary uses rules to separate code in data
from other code and other data if it's defined in this way a boundary specifies that a code that is
launched on one side of the boundary shouldn't access the code and data of the other side or that the
Access has to be controlled by an explicitly defined rule.
The rules have to be intuitive enough so that the user can grasp and follow them.
This means that an OS developer.
In this case Microsoft has to maintain the defined boundary developer has to react to all violations
of the boundary and all attempts to cross it.
If the security boundary is to isolate some processes it has to be worth the time and money it will
cost to maintain it.
Rules are used for a boundary have to be said explicitly You can't be a state border or the sort of
border that you only need to slow down to cross through.
It should be more like the border between North and South Korea.
High fences barbed wire and a minefield in between the boundary has to be strong enough to make unauthorized
passage impossible or at least significantly hinder it.
If we assume it as such it turns out that maintaining security boundaries could incur too great a price
not only for a system developer but above all for users.
If you had a chance to work with Windows Vista you could witness this in practice the system and forced
a strict boundary between administrator and user account roles an example of this was windows pop ups
that repeatedly asked whether you really wanted to execute an operation Microsoft has learned their
lesson and new versions of the system were less bothersome although as we'll see soon the boundaries
still exists.
The more boundaries the system implements the less user friendly it becomes.
You can't put too much weight on security by reducing functionality
violation of a security boundary has to be met with a prompt reaction from the software developer or
otherwise boundaries wouldn't perform their function.
One peculiar thing about cybercrime is that developing an attack technique requires specialized knowledge
commitment and also money but a subsequent use of a premade scenario is much easier after a given vector
becomes automated.
It's a walk in the park and the boundary crossing has to entail an immediate reaction from software
developers
a consequence of the outlined assumptions is the fact that operating systems including Windows implement
a lot fewer security boundaries than it would seem.
It's worth noting that there's much fewer boundaries than the marketing materials that sing the praises
of SLR the Epi and other security solutions would have you believe as it will turn out.
The solutions don't necessarily define any security boundaries.