>> Hi everybody.
In addition to the STRIDE Model,
we can also look at creating use and misuse cases.
In this case, we start with
the user who is ultimately going to
try to access an application server. That's their goal.
The very first step is that they're going
to enter their username and password.
Of course, that password serves as authentication.
With that first step, what are the threats here?
Well, a big threat is that there is
a brute force authentication attempt.
A brute force attack is where a hacker could try using
every character combination possible
to guess the username and password.
Or the attacker could just
guess the username and password
based on what the hacker already knows
about usernames at the organization,
in common passwords people use.
Finally, the hacker could try dictionary attacks.
Dictionary attacks involve using
a text file with many gigabytes of possible entries,
including those that contain special characters.
Dictionary attacks have become
much more sophisticated over
the years since so many users
include special characters in their passwords now.
How do we mitigate against these threats?
One way we do this is to show
a generic error message when
the hacker gets the password wrong.
We don't provide a specific error message
about what was wrong in the failed attempt.
Another thing we can do is lock
an account after a certain number of failed attempts.
That will prevent an automated program from being
able to keep running and trying different combinations.
Another way to mitigate against
these threats is to require users
to have passwords that have
a minimum length and a certain amount of complexity.
Complexity does not always equal security.
These days, we recommend that users create
longer passwords rather than more complex ones.
This gives you an idea of how use,
misuse case works and how it
>> is used for threat modeling.
>> You could take this same model to look at the case
of an individual trying to access a file.
You would consider the threats and
vulnerabilities and how they could be exploited.
Then you would consider the mitigation strategies.
Another way to do threat modeling,
which is not shown on this slide is risk scenarios.
This is where you simply list your assets,
then list all the things that
could threaten those assets.
Then you could list the vulnerabilities.
Many play the what-if game to
consider the scenarios that could threaten your assets.
The most important thing is to consistently
document your risks so you
can figure out how to mitigate them.
To wrap up risk identification,
we started off by talking about risk management and
reducing residual risk to
a level acceptable to senior management.
Then we talked about looking at
our assets as well as the threats and
vulnerabilities and where those come
together. That is our risk.
The tool we talked about for identifying
risk is to use threat modeling.
For this, we can use
the STRIDE Model or the use misuse cases,
or it can be risk scenarios.
The most important thing to
remember is that with risk management,
you have to start with the risk identification first.