- [Narrator] Authorization is the final step
in the access control process.
Once an individual successfully authenticates to a system,
authorization determines the privileges
that individual has to access resources and information.
There are many different authorization approaches,
and we'll discuss those in this course.
First let's talk about two general principles
of authorization that lead to strong security.
First the principle of least privilege.
This principle states that an individual
should have only the minimum set of permissions
necessary to accomplish his or her job duties.
Least privilege is important for two reasons.
First, least privilege minimizes the potential damage
from an insider attack.
If an employee turns malicious,
the damage they can cause will be limited
by the privileges assigned to them by a job role.
It's unlikely, for example, that an accountant
would be able to deface the company website
because an accountant's job responsibilities
have nothing to do with updating web content.
Second, least privilege limits the ability
of an external attacker to quickly gain
privileged access when compromising an employee's account.
Unless they happen to compromise
a system administrator's account,
they will find themselves limited
by the privileges of the account that they steal.
The second important principle is separation of duties.
This principle states that sensitive business functions
should require the involvement of at least two people.
This reduces the likelihood of fraud
by requiring collusion between two employees
to commit fraud.
One common example of separation of duties
is found in accounting departments.
One way that employees might steal funds
from the organization is to set up fake vendors
in the system and then issue checks to those vendors
for services that were never rendered.
To prevent this, organizations typically separate
the ability to set up a new vendor
and issue a check to that vendor
and say that no employee should ever have both
of those privileges.
Organizations must watch out for privilege creep
when trying to follow the principles of least privilege
and separation of duties.
Privilege creep occurs when users change
from one job to another and gain new privileges
accessed with their new responsibilities
but never lose the privileges
from the job that they left.
Over time an employee who moves around
from role to role may gain substantial privileges
in this way.
Consider the example of Alice.
Alice starts as a clerk in the accounting department,
where she is responsible for issuing checks to vendors.
There, she has the issue check privilege.
After a few years, Alice receives a promotion
to a supervisory accounting position
and gains responsibility for starting up new vendors
in the system.
Number ever takes away her old privileges.
Alice now has the ability to both set up
a new vendor and issue checks,
a violation of both least privilege
and separation of duties.
Organizations looking to preserve
the principles of least privilege and separation of duties
should perform regular account reviews.
These may come in both manual and automated forms.
For example, an automated process
might run every time a user is granted new privileges
to ensure that the new privileges won't violate
any separation of duties requirements.
The organization might supplement these automated checks
with quarterly access reviews
where managers manually review the permissions assigned
to each employee for compliance
with the principle of least privilege.
Maintaining authorization systems is a critical task
for security professionals.
The CISSP exam might contain a question
asking you to review a scenario
and describe what authorization principle
is being described.
Be sure to know the difference
between least privilege and separation of duties
so that you're ready for those exam questions.