>> Hi everybody. As you can tell
from the information we've covered so far,
risk management is a huge part of information security.
Let's go ahead and take a closer look at some of
the processes of the risk management lifecycle.
What are the steps of the risk management lifecycle?
We start by identifying risks
and determining where threats meet vulnerability,
then we assess the risks.
We use qualitative or quantitative analysis
to determine what potential is for loss.
In order to do that, we're
going to look at the probability
of the risk event and multiply that times its impact.
This gives us value of the risk so we can prioritize it.
Then we mitigate the risks.
The value of the risk that we assessed in
Step 2 will drive our mitigation strategy.
If it's a high probability,
high impact risk,
will have a very active strategy.
If it's a low-probability,
low-impact risk, will probably have a passive strategy.
Our options for mitigating risks are by reducing,
transferring, or accepting risk.
Then we monitor the risks because
we know we can't eliminate risks completely.
We must continue to monitor.
If someone asks, "When are
you done with risk management?"
The answer is never because you
have to continue to monitor for risks.
First step, risk identification.
There are three parts to risk identification we
have: identify assets,
identify threats, identify vulnerabilities.
Frequently when we talk about assets and
information security, we mean data.
We have to identify the data we
want to protect and the value of the data.
Then the next part is to ask, what are the threats?
Again, threats are those elements that
can exploit weaknesses or vulnerabilities.
You have to identify the vulnerabilities.
Now, one of the ways we can
identify risk is to use threat modeling.
STRIDE is a common threat model
that we'll look at in a second.
Another type of threat model is use misuse cases.
You could also include
risk scenarios as a type of threat model.
The STRIDE threat model is
a very common model that is
used with software development.
It includes six primary security threats
and the mitigation strategies for each of those threats.
The first letter of each threat spells the word STRIDE.
Spoofing is the S in STRIDE and it means impersonation.
It could be IP address spoofing,
caller ID spoofing, MAC
address spoofing, or email spoofing.
The best way to mitigate against
spoofing is strong authentication,
which is proving your identity.
Usually, we want to use
multiple factors of authentication.
This typically includes asking
you for something you know,
something you have, and something you are.
Recently, we've added somewhere you are using
GPS and we've also added something you do.
This could be patterns that you
swipe on your smartphone and so forth.
Tampering is the next threat and it's the T in STRIDE.
This involves some modification.
The best way to mitigate against
this threat is the reform of
integrity verification such as message digests.
Another word for message digest is a hash.
We'll talk more about that in just a bit.
Another older mitigation strategy is
CRCs, cyclic redundancy checks.
Another strategy is checksums.
Repudiation is the next threat in
this model and it's the R in STRIDE.
This means that a sender of
an email disputes that they sent
the message or they could say that they sent the message,
but it was tampered within transit.
The mitigation strategy is non-repudiation.
This means using something that provides authenticity and
integrity such as a digital signature and keys.
We'll talk more about this in
our section on cryptography.
Information disclosure is the I in STRIDE.
This means the disclosure of sensitive information.
We mitigate this through confidentiality and encryption.
Denial of service is
the next threat and this is the D in STRIDE.
Denial of service attacks are about
rendering a service or server unavailable.
This might be where you flood a server with
illegitimate reasons so that it
is so busy dealing with
those requests it can't handle legitimate requests.
Another example is where an attacker uses
unsuspecting networks that we refer to
as botnets or zombies to launch
a much larger scale attack on the target.
The mitigation strategy for
this type of threat is high availability,
redundancy, and fault tolerance.
If web server 1 is attacked that's okay
because web server 2 can handle this remaining traffic.
Escalation of privilege is the E in STRIDE.
This threat means an attacker accesses a system as
a regular user and escalates his privileges,
that way he has an admin account,
for example, and can give more permissions.
The mitigation strategy for this is to
have strong authorization measures.
To recap, STRIDE is a great start to threat modeling.
It looks at six of the most common threats
and how to mitigate them.